fire service manual volume 1 fire service …...1.4 home office communications advisory panel...

Issued under the authority of the Home Office(Fire and Emergency Planning Directorate)

Fire Service Manual

Volume 1Fire Service Technology,Equipment and Media

CommunicationsandMobilising

HM Fire Service Inspectorate Publications Section

London: The Stationery Office

© Crown Copyright 1998Published with the permission of the Home Officeon behalf of the Controller of Her Majesty's Stationery Office

Applications for reproduction should be made inwriting to The Copyright Unit, Her Majesty's Stationery Office,St. Clements House, 2-16 Colegate, Norwich, NR3 1BQ

ISBNO 11 3411855

Cover photographs:

Upper: Surrey Fire and Rescue Service

Lower: London Fire Brigade

Half-title page photograph:

Hertfordshire Fire and Rescue Service

Printed in the United Kingdom for The Stationery OfficeJ50973 7/98 C50 5673

Communicationsand Mobilising

Preface

The first edition Part 5 of the Manual ofFiremanship dealing with the subject of communi-cations was issued in 1954. It concluded "FireService communications are intimately related toan intricate field of electrical engineering, whichincludes telecommunications both by landline andwireless, which is in turn only a small part of theterritory covered by electrical science".

The passage of time and advances in technologyhave changed every concept of fire service com-munications from those identified by the writerswithin the first edition of Part 5. The basic fire ser-vices' communications requirements have, howev-er, remained unchanged and are identified in the1947 Fire Services Act. This is still as relevanttoday as it was when first mandated to fire author-ities in 1947, to "secure efficient arrangements fordealing with calls for the assistance of the firebrigade in case of fire and for summoning mem-bers".

To ensure that fire services' communications effi-ciency is maintained to the highest level requiresthe introduction of modern technology systems,coupled with frequent reviews to brigades' prac-tises and procedures. Changes in equipment andprocedures become inevitable, because eitherequipment becomes obsolete, or technical main-tenance support is exhausted or overly expensive.New equipment often has advantages over what itreplaces, in that it generally incorporates morefunctionality and flexibility, thus affordinggreater opportunities for changes in proceduresand practises.

It is an impossible task to bring the reader fully up-to-date with the technology that is both availableand continually evolving, or indeed to indicate that

which may be available in the future. This book iswritten in non-technical terms and aimed primari-ly at covering the operational and functional com-munications requirements of the professional fire-fighter. This, by necessity, encompasses all thecommunicating elements from that of "the origi-nating caller to the incident's conclusion" via thebrigade Control, station call-out and IncidentCommand structures. The text, diagrams and sym-bols used, whilst not necessarily conforming tothose in other technical publications, have beenmodified as appropriate to assist the reader. Thosewho require further technical detail must refer toother publications and technical sources whichspecialise in the area concerned.

It is anticipated that this book will be invaluable tobrigade Communications Officers and all person-nel who are or become intimately involved in theplanning, procurement, implementation and opera-tion of mobilising systems, communications sys-tems, radio and fixed and mobile communications.As in Book 10 of the Manual of Firemanship, agreat deal of emphasis has been placed upon plan-ning principles, and the importance of clearly iden-tifying both the operational requirements and theconstraints associated with procurement processes.New technology solutions can be both implement-ed and beneficial if, as a result of a due planningprocess, they address and meet the needs and cri-teria of 'the user'. New technology should not,however, be seen as the driving force and the rea-son to change for changes sake. This is especiallyso in areas where an overall simpler solution couldbe adopted instead.

It is hoped that the information and advice con-tained within this book will help to ensure that theFire Services' Communications and associated

Communications and Mobilising iii

systems will at least maintain and ideally improvetheir present standards of efficiency and reliability.

The Home Office is greatly indebted to all thosewho have contributed and assisted (by providingmaterial and information) in the preparation of theedition.

This book replaces the Manual of FiremanshipBook 10 Fire Brigade Communications andMobilising.

Home OfficeJune 1998

iv Fire Service Manual


Contents

Preface Hi

Chapter 1 Regulatory issues 1

1.1 H.M. Government 21.2 OFTEL 21.3 Radio Frequency Management 31.4 Home Office Communications Advisory Panel (HOCAP) 8

Chapter 2 Fire Control Centres 112.1 Basic Call Handling Procedures 11

2.2 Control Centre Staffing Levels 15

Chapter 3 A brief history of the 'Fire Control Centre' 17

Chapter 4 The 999/112 emergency service 234.1 BT 234.1.1 The British Telecom fixed telephone system 234.1.2 Operator call-handling procedures 244.1.3 Mismatches between EA and Fixed Network Operator Boundaries 264.1.4 Provision of ex-directory information 264.1.5 Access to tape recordings of Emergency Calls 264.1.6 Calling Line Identity (CLI) 274.1.7 Network Resilience 284.1.8 Priority Fault Repair Service 284.1.9 BT National Emergency Linkline 284.1.10 Government Telephone Preference Scheme 294.1.11 Secondary Control 304.1.12 Publicity/Public Education 304.2 Cable & Wireless 999 service 304.2.1 Operator call-handling procedure 314.2.2 Enquiries and requests from emergency services 324.3 Kingston Communications 324.4 Telephone Number Portability 334.5 Emergency Text Telephone Service for the deaf 334.6 Emergency calls from the Railway Industry Network 344.6.1 Paypnones 354.7 Cellular communications 354.8 Cellular 999 services 354.8.1 Name and Address Information of Mobile Callers 364.8.2 Release of Subscriber information 364.8.3 System Description - ORANGE 37

Communications and Mobilising V

4.8.4 Cell/EA Boundaries4.8.5 Routing 999/112 Calls to EACCs4.8.6 Cell ID Look-Up Failure4.8.7 EACC Connect-to Numbers4.8.8 Misrouted Calls4.9 The satellite telephone4.10 Public Warning and Information by Telephone (PWIT)4.10.1 How the proposed BT 'PWIT' system would work

C h a p t e r 5 Control Centre e q u i p m e n t

5.1 Control Centre Design5.2 Communications5.2.1 Administrative Communications5.2.2 Safeguards for Emergency Communications5.2.3 Provision of Suitable Circuits5.2.4 Alternative Routing of Cables5.2.5 Monitoring of Remote Circuits5.2.6 Exchange Telephone Lines5.2.7 Operational Lines5.2.8 Line Concentrator Units and Digital Switches5.2.9 Automatic Call Distribution5.3 Computerising Mobilising System5.3.1 Mobilising System Functions5.4 Ancillary Control Facilities5.4.1 Voice Recorders5.4.2 Availability and Fire Situation Display5.4.3 The Gazetteer5.4.4 Maps5.4.5 Automatic Fire Alarm (AFA) Terminations5.4.6 Secondary Control Facilities5.4.7 Control Centre Software5.5 Equipment at Fire Stations5.5.1 Mobilising Computer5.5.2 Printers5.5.3 Alerter Base Station5.5.4 Public Address System5.5.5 Turnout Lighting5.5.6 Alternative Power Supply5.5.7 Exhaust Extraction Systems5.5.8 Control of Traffic Signals5.5.9 Automatic Appliance Room Door5.5.10 Running Call Facilities5.5.11 Enquiry Bell5.5.12 Other Ancillary Equipment

C h a p t e r 6 A u t o m a t i c Fire A l a r m Transmiss ion S y s t e m s

6.1 Transmission Methods and Reliability Issues6.2 Social and Community Alarms Centres

3737383838393940

4 3

44444444454545464646484848515152525353545454545454545555555556565656

57

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vi Fire Service Manual

Chapter 7 Automatic Vehicle Location Systems 637.1 AVLS Technology 647.2 Potential Benefits of AVLS to the Fire Service 667.3 AVLS System Implementation 667.4 Operational Considerations 677.5 Implementation Costs 677.6 Conclusions 68

Chapter 8 Smart and Swipe Cards 69

Chapter 9 CCTV in the Fire Service 71

Chapter 10 Radio 7510.1 Frequency Spectrum characteristics, selection and allocation 7510.1.1 The Frequency Spectrum 7510.1.2 Characteristics of the different Frequency Bands 7710.1.3 Frequency Selection and Allocation 7810.1.4 Channel Spacing 7910.2 Radio Scheme Engineering 7910.2.1 Modulation methods 7910.2.2 Talk-through 8110.2.3 Wide Area Coverage 8210.2.4 The Spaced Carrier System 8210.2.5 The 'Quasi-Synchronous' or 'Common Frequency' System 8210.2.6 Scheme Engineering 8310.2.7 Links 8310.2.8 Frequencies 8410.2.9 Equipment 8510.2.10 Fixed Mobiles 8610.2.11 Main Control 8610.2.12 Transportable Equipment 8710.2.13 Power Supply Arrangements 8710.2.14 Microwave 8710.2.15 Multiplexing 8810.3 Mobile, Transportable and Personal Radio Equipment 8910.3.1 Conventions 8910.3.2 Mobile Equipment 8910.3.3 The Aerial 9010.3.4 Channel Selection 9010.3.5 Squelch 9010.3.6 Transmission Timer 9010.3.7 Power Supplies 9110.3.8 Fixed Mobile Version 9110.3.9 Special Features 9110.3.10 Transportable Equipment 9210.3.11 Personal Equipment 9310.3.12 Methods of using Personal Radios 9310.3.13 Composite Units 9510.3.14 Personal Hand-Held Radio Sets 9610.3.15 Intrinsically Safe Personal Radios 96

Communications and Mobilising vii

10.3.16 B.A. Radio Communications Interfaces 9610.3.17 Disadvantages of use of radio with B.A. 9610.3.18 User Discipline 9610.3.19 Security 9710.3.20 Care of Hand-Held Radio Equipment 9710.4 Trunked mobile radio systems 98

Chapter 11 Radio Alerting System 9911.1 Alerter - General Description 9911.2 Encoder 10011.3 Transmitter 10111.4 Alerters 101

Chapter 12 Mobile Data 10312.1 What is Data? 10312.2 History 10312.3 Current Technology 10412.4 Radio Communications 10412.5 Data on Vehicles 10512.6 Typical Data Requirements 10612.7 Mobile Control Units 108

Chapter 13 Breathing Apparatus Telemetry 109

Chapter 14 Sub-surface communications 113

Chapter 15 Potential hazards of using radio equipment 11515.1 Explosion Protection - Standards 11515.2 Ignition Sources 11615.3 Protective Measures 11615.4 Intrinsically Safe Design Criteria 11715.5 Selection of Explosion Protected Equipment 11715.6 Radio Use in the Vicinity of Explosives, etc. 11815.7 Radio Use in the Vicinity of Retail Petrol Stations, etc. 11815.8. Radio Use in the Vicinity of Air Bags 11815.9 Radio Use in the Vicinity of Medical Devices 118

15.10 Radio Use within Silos 119

Glossary of terms and abbreviations 121

Appendix 1: Control Staff- Training, Competence and Promotion 127Fire Service College Courses 128Brigade Based Initial Recruit Training 129Appointment and Promotion of Control Personnel 131Standards of Competence 132

Appendix 2: List of relevant DCOLs/DFMs (in Scotland) and FSCs 134

Acknowledgements 135

viii Fire Service Manual


Chapter 1 - Regulatory issues

1.1 H. M. Government

Members of Her Majesty's Government responsi-ble for the fire service are:

Secretary of State for the Home Department.(England and Wales);

Secretary of State for Scotland; andSecretary of State for Northern Ireland.

Parliamentary Under-Secretaries of State

(Fire and Emergency Planning, Prisons, etc.)

Director Fire and Emergency Planning

Her Majesty's Chief Inspectors of Fire Services

Central Government Responsibility forthe Fire Service

While Fire Authorities have statutory responsibili-ty for the provision of fire cover and exercise day-to-day control over activities of their fire brigades,the Home Secretary has a central responsibilityfor the efficiency of the fire service and is answer-able to Parliament on fire policy. Assistance isgiven to Fire authorities by the Home Office inestablishing standards and the provision of techni-cal guidance.

In England and Wales, the Home Office Fire andEmergency Planning Directorate advises theHome Secretary on fire matters including the oper-ational efficiency of the fire service and theenforcement of fire safety legislation. FireBrigades are inspected by HM Fire ServiceInspectorate. The Inspectorate also provides thetechnical resource for compilation of codes ofpractice and guides, to legislation for the benefit ofFire Brigades.

HM Chief Inspectors provide reports to the rele-vant Secretary of State.

Fire Service Funding

In England and Wales, fire services are providedeither by County Councils or Combined FireAuthorities in the shire, and by joint Fire and CivilDefence Authorities in London and the formermetropolitan counties.

Some funding is provided from central govern-ment as part of a composite revenue support grantmade to local authorities, the remaining cost is col-lected through the revenue support mechanism ofthe council tax. The Fire Service, unlike the PoliceService, receives no specific grant from centralgovernment.

The money distributed for the fire service(Standard Spending Assessments) is not ring-fenced within the total amount available to thelocal shire authorities (Total Standard Spending)and the shire fire brigade has to compete withother local authority services for its resources. TheFCDAs have no other sources of funding. TheCombined Fire Authority (CFA) is financed bycontributions from its constituent authorities, whoare required to meet their proportionate share ofsuch expenditure.

Capital expenditure by fire authorities may befunded from borrowing, capital receipts (subjectto certain rules), or from revenue expenditure.The Home Office sanctions borrowing for firecapital expenditure generally through the alloca-tion of Basic Credit Approvals (BCAs) andSupplementary Credit Approvals (SCAs) forspecific purposes.

Communications and Mobilising 1

The Central Fire Brigades AdvisoryCouncil

In England and Wales, except on discipline andconditions of service matters, the Home Secretaryis advised in the discharge of his/her responsibili-ty for fire by the Central Fire Brigades AdvisoryCouncil (CFBAC). This council was set up underSection 29 of the Fire Services Act 1947 and isnormally chaired by a Home Office minister andincludes representatives of the local authorities,the fire service and other interested organisations.A similar council advises the Secretary of State forScotland.

The CFBAC is in turn advised by a number ofstanding committees, and ad hoc committees arealso established from time to time to consider orreview particular policies. By agreement betweenthe Home Secretary and the Secretary of State forScotland, these standing committees are joint com-mittees which advise both the Council for Englandand Wales and the Council for Scotland.

The Chairman of the Central Fire BrigadesAdvisory Council is usually the ParliamentaryUnder Secretary of State with specific responsibil-ity for fire service matters.

The subject matter in this section of the manual isdealt with by the Joint Strategy Committee onOperational Practices and Technology.

Fire Service communication issues are also discussedwithin the Chief and Assistant Chief Fire Officers'Association (CACFOA) committee structure.

Communications and Computing PolicyCommittee (C&CPC) - at Chief Officer level.

District Communications Working Parties -at Control and Communication Officer level.

Home Office 999 Liaison Committee

The Home Office organises and supports meetingsof the 999 Liaison Committee, a forum whichbrings together representatives of the EmergencyAuthorities (EAs) - (Police, Fire, Ambulance andCoastguard), the Public TelecommunicationOperators (PTOs) (fixed and mobile) and other

organisations with an interest in the 999 service.These include HM Fire Service Inspectorate, TheScottish Office, OFTEL and the Department ofTrade and Industry.

The Committee, which meets twice a year underthe chairmanship of the Home Office, discussesissues and matters arising from the provision of the999 public emergency call service. The Committeeencourages liaison between the EAs and PTOs at amore local level and considers what mechanismmight be introduced to resolve disputes betweenthe EAs and PTOs. It has also introduced Codes ofPractice and Memorandums of Understanding,covering such issues as methods of handling 999emergency calls on the fixed and mobile telephonenetworks.

The 999 Liaison Committee was responsible forproducing the 'Strategic Framework forCombating Malicious Hoax 999 Calls' issued asDCOL 9/96 (in Scotland as DFM 8/1996).

Any problems which need to be resolved are pro-gressed through a spirit of co-operation and good-will between the relevant parties; the 999 LiaisonCommittee has no statutory powers or authority.

The Joint Strategy Committee on OperationalPractices and Technology receives regularupdate reports from the 999 LiaisonCommittee.

1.2 OFTEL

The Office of Fair Trading for Telecommuni-cations, OFTEL, is the regulator - or 'watchdog' -for the UK telecommunications industry. It isheaded by the Director General of Telecommuni-cations. The Director General is appointed by theSecretary of State for Trade and Industry and theappointment usually runs for five years.

OFTEL was set up under the TelecommunicationsAct 1984. OFTEL regulates through monitoringand enforcing the conditions in all telecommunica-tions licences in the UK, and initiates modifica-tions to these licence conditions.

All telecommunications operators - such as BT,Cable & Wireless (formerly Mercury), local cable

2 Fire Service Manual

companies, mobile network operators and theincreasing number of new operators - must havean operating licence. These set out what the oper-ators can - or must - do or not do.

Under the Telecommunications Act 1984, OFTELhas a number of functions.

These include:

ensuring that licensees comply with theirlicence conditions;

advising the Secretary of State for Trade andIndustry on telecommunications matters andthe granting of new licences;

obtaining information and arranging for pub-lication where this would help users; and

considering complaints and enquiries madeabout telecommunications services or appa-ratus.

Under the Act, the Director General has a duty tocarry out these functions, some of these dutiesinclude:

ensuring that telecommunications servicesare provided in the UK to meet all reasonabledemands for them (this includes emergencyservices, public call boxes, directory informa-tion services and services in rural areas);

promoting the interests of consumers;

ensuring that those providing services aredoing so efficiently; and

promoting research and development.

The Director General has extensive powers underthe Telecommunications Act, particularly whenenforcing or modifying licence conditions. He candirect licence holders to comply with a certaincondition - or conditions - in their licences. If theycontinue to breach the same condition/s theDirector General can make orders which areenforceable through civil action.

OFTEL is also responsible for administering the

numbering scheme in the UK and allocates blocksof telephone numbers to operators. A separateNumbering Administration Unit within OFTELdeals with this.

OFTEL monitors developments overseas.Nowadays UK operators are international busi-nesses and so are their major customers. OFTELtakes a global view and ensures that UK policiesand decisions reflect international develop-ments, they are also closely involved withtelecommunications developments in theEuropean Union.

OFTEL is a non-ministerial government depart-ment, and is, therefore, independent of ministerialcontrol.

Each year the Director General is required to submitan Annual Report on the department's activities andthose of the Monopolies and Mergers Commission(MMC) in the telecommunications area, to theSecretary of State. This is laid before Parliament.

Funding is provided by Parliament, but the cost isoffset almost entirely by the licence fees paid in bythe operators.

OFTEL staff are Civil Servants, and experts fromconsumer, business and industrial backgrounds.The Director General also has six AdvisoryCommittees to advise him on telecommunicationsmatters. The only one of these committees that hasa direct relevance to the Fire Service is theAdvisory Committee on Telecommunications forElderly and Disabled People (DIEL).

One OFTEL proposal was the introduction of a BT'Lifeline' service. This service which gives provi-sion for 999/112 calls also allows incoming callsfor a few pence a month. A change to the discon-nection policy may include barring of outgoingcalls as an alternative to disconnection, emergencycalls could still be made.

1.3 Radio Frequency Management

'Frequency' management in the United Kingdomis an inter-departmental function of central gov-ernment accountable to a cabinet committee. Twosub groups and a small secretariat are responsible


for the general radio frequency planning andassignment procedures on behalf of this commit-tee.

The Frequency Planning Group is formed fromrepresentatives of all government departments andagencies involved with frequency management. Itexamines proposals from departments to ensurethat applications are compliant with the terms andconditions set out in the International RadioRegulations (IRR) and are consistent with effec-tive use of the available spectrum. From time totime it may agree to assign a service or applicationoutside the terms defined in the IRR. In such casesthe group must be satisfied that no harmful inter-ference will result to services operating in accor-dance with the Radio Regulation Tables.

The Assignment Panel is broader based andincludes representatives from Industry as well asgovernment departments and agencies. The panelexamines all proposals to use shared radio bands.Its primary responsibility is to ensure that noharmful interference results from the shared use ofradio bands or to the dedicated bands which areallocated to various services/applications.

Radiocommunications Agency

The Radiocommunications Agency (RA) wasestablished as an executive agency of theDepartment of Trade and Industry (DTI) on 2ndApril 1990. Previously the RA operated as DTI'sRadiocommunications Division.

The Agency is responsible for most civil radiomatters, other than those of telecommunicationspolicy, broadcasting policy and the radio equip-ment market. The main activities are:

licensing the use of radio equipment underthe Wireless Telegraphy Act 1949;

investigating interference and enforcing therelevant legislation;

representing United Kingdom interests ininternational meetings on radio spectrummanagement matters;

seeking to ensure that all United Kingdomusers, manufacturers and installers of radioequipment comply with the relevantEuropean Union measures and with the rele-vant provisions of international agreements towhich the United Kingdom is a party;

developing policy for, and planning and reg-ulating use of the radio frequency spectrum,the geostationary orbit and other orbits oftelecommunications satellites by all non-government users of radio equipment in theUnited Kingdom except where otherwiseagreed; and

monitoring the radio frequency spectrum asan aid to its management, enforcement, andensuring freedom from harmful interference.

Radio Investigation Service

The Radio Investigation Service (RIS) is theenforcement arm of the RadiocommunicationsAgency. Its aim is to ensure that authorised radiousers can operate without undue interference. Thisis achieved by ensuring that licensed users adhereto the conditions under which they are authorisedto operate and, if necessary, by taking legalenforcement action against those who operateradio equipment without regard to other authorisedusers.

The RIS has several roles:

resolution of interference problems;

inspection of installations at customer'spremises; and

help and advise with radio problems and offera paid diagnostic service to commercial anddomestic radio users.

The RIS inspects all Police and Fire Service radioinstallations as part of their work. This is to ensurecompliance with the conditions of the radiolicence. The RIS has indicated that it will contactusers beforehand to arrange a convenient date andtime for the inspection.


Role of the Home Office in FrequencyRegulations and Management

The Home Office (Scottish Office in Scotland)participates in national frequency management inthe United Kingdom, and is accountable to theCabinet Office. These departments also providerepresentation through the RA in international fre-quency management fora.

The maintenance of inter-operability between indi-vidual users is a major operational requirement ofboth the Police and the Fire Service. This has a sig-nificant influence on radio scheme engineeringand spectrum planning. Where an individual forceor brigade propose changes to their radio schemesthat are likely to affect the level of current inter-operability, the department takes advice fromnational user representatives before granting thenecessary assignments.

Policy and Regulation

The Home Office Frequency Management Groupassigns frequencies to its user services to meetspecified operational requirements. Wherever pos-sible, this takes account of national and interna-tional frequency management policies.

Home Office policy is promulgated to users in theform of "Radio Frequency Policy Statements".Separate series of policy statements are preparedfor both the Police and for the Fire Service

These documents, which are classified as'Confidential' under the Government ProtectiveMarking Scheme, are sent to all Chief Officers ofPolice, and Fire Services, and to certain otherinterested parties such as the Radiocommuni-cations Agency. The documents form the basis onwhich assignments are licensed and regulated.

Radio Frequency Policy Statements can includeoperational limitations on the use of channelswhere it is considered necessary to maintain theefficient use of the radio spectrum.

Type Approval

To provide the most efficient use of the availableradio spectrum, and avoid undue levels of interfer-

ence between systems, it is essential that all radioequipment meets minimum standards of perfor-mance. Type approval is a procedure whichinvolves checking the technical characteristics ofnew equipment, or modifications to existingequipment, to ensure that the design meets thesestandards and is acceptable for licensing. Typeapproval is only intended to provide a means ofexamining an equipment's potential for causing orsuffering radio interference. It is not an endorse-ment or recommendation of a particular device foroperational use.

If transmissions other than those of therequired frequency (Spurious transmissions) areradiated by transmitters, then this is likely tocause interference to other radio receivers.

For civil radio spectrum users, these performancestandards are published in a series of specificationsissued by the RA. Similarly, equipment used inHome Office bands must also meet certain stan-dards to satisfy the conditions of the users' licence.

The Home Office sets its own standards of perfor-mance for equipment used in its bands. Currently,these are based, where possible, upon the appro-priate MPT*, or European TelecommunicationsStandard Institute (ETSI), specification. Wherethere are no relevant specifications. RadioFrequency and Communications Planning Unit(RFCPU) publishes its own. These set out the car-dinal points to which equipment must complybefore it is considered for licensing. The relevantHome Office Radio Frequency Policy Statementshould be consulted for advice on the typeapproval of equipment to be used in Home Officebands.

Only approved equipment is licensed under cur-rent regulations and users are advised to check thesuitability of any apparatus before making a finan-cial commitment. Use of non-approved equipmentcontravenes the conditions of the comprehensiveradio licence held by each Police force, FireBrigade or other user of channels in the HomeOffice bands. Separate additional approval is

* MPI is an abbreviation for Ministry of Post andTelecommunications. Although this Ministry no longerexists, the RA is still using the initials MPT plus anumber to indicate their specification documents


required from the Civil Aviation Authority (CAA)for equipment used in aircraft.

Radio call-signs

The Home Office RFCPU is responsible for theallocation of call signs to all fire brigade radioschemes. The detailed allocation of identifyingsuffix letters and/or figures to individual units(mobiles, etc.,) is arranged locally. The call signsfor all police and fire brigade radio schemes startwith 'M2' followed by two letters which identifythe particular radio scheme, e.g., M2FH. The useof call signs, and radio operating procedures gen-erally, are dealt with in the Fire Service TrainingManual. The basic call sign of a fire brigade isshown on the brigade radio licence.

Home Office Frequency ManagementGroup

The Home Office Frequency Management Group(HOFMG) is part of the Radio Frequency andCommunications Planning Unit (RFCPU). TheScottish Office regulates frequencies forScotland.

The main functions of the Frequency ManagementGroup are as follows:

Regulation and management of the frequencybands allocated for Home Office user ser-vices in accordance with national and inter-national policies.

Assignment of frequencies to meet specificuser requirements in the Home Office bandsat HF, VHF, UHF and SHF.

Preparation and maintenance of licenceschedules for Home Office user services andmaintenance of a database of all assignmentsin the Home Office bands.

Represents the Home Office and its user ser-vices within the national frequency planningforum.

Provides representation, through the Radio-communications Agency, at international fre-quency management forums.


Promulgation of policy regarding the use ofthe department's band allocations through thepublication of a series of Radio FrequencyPolicy Statements.

Represents Home Office user services onDTI and National committees i.e.. Civil andLand Mobile Committee (CLMRC) andMicrowave Fixed Links Committee (MFLC).

Technical assessment of applications to sharePolice and Fire Service hilltop and othersites, to determine the potential risk of inter-

Assist Home Office user services with inter-ference problems.

The Police and Fire ComprehensiveRadio Licence

In accordance with the Wireless Telegraphy Act(1949) all users of radio frequencies must belicensed by the Secretary of State. The organisa-tion responsible for issuing radio licences orauthority to use frequencies is the Radiocommuni-cations Agency.

The 'Police and Fire Comprehensive RadioLicence' has been designed to cover all HomeOffice managed frequencies assigned to a particu-lar user. Any assignments that a user holds whichare in civil bands will need to be licensed sepa-rately. The only exception is 'Citizen Band' (CB)channels which are covered by the Police and FireLicence.

For the fire service the licensee referred to in thelicence document is normally the Chief FireOfficer. Under the terms of the licence, thelicensee shall only use the Fixed Stations andMobile Stations to send and receive wireless teleg-raphy relevant to the operation of the fire services.

Private Contractor Access to FireAssignments in the Home Office Bands

With reference to the relevant Home Office RadioFrequency Policy Statement, where private contrac-tors are responsible for the provision and/or mainte-nance of Fire Service radio systems, their staff may

have access to certain Brigade frequency assign-ments and be required to use these for the purposesof test transmissions. The Home Office will autho-rise the use of such frequencies within the Brigadearea by private contractors, subject to the prioragreement of the respective Chief Officer. Use ofBrigade frequencies at service centres remote fromthe Brigade area may be permitted conditionally, butwith prior approval from the Home Office RadioFrequency and Communications Planning Unit.

Such contractors will be required to hold a Testand Development (T & D) Licence relevant toeach Brigade to whom they remain responsible. T& D licences, which cover the repair and servicingof radio equipment are issued by theRadiocommunications Agency, and are subject torenewal annually on payment of the appropriatefee. During the tendering stage, Brigades shouldensure that private contractors are made aware ofthe requirement for their work to be covered by aseparate T & D licence.

Licenses for other frequency bands

The Police and Fire Comprehensive Radio licencedoes not authorise use of any frequencies otherthan those in the Home Office frequency bands. Itis, therefore, necessary to apply for a separatelicence from the Radiocommunications Agencyfor each channel. A separate licence fee ispayable for each licence.

Use of Radio Channels in an Emergency

No automatic right exists for any authority or per-son(s) to use any frequency not allocated to them.However, in specific circumstances, e.g., an emer-gency, or for carrying out tests associated withmaintenance and repair activity, such authoritymay be prior issued in writing or verbally. If anemergency situation exists, such person(s) must,at all times, utilise correct voice procedureswhich specifically ensure that the call sign of thecorrect licensee is used with specific suffixesallocated to 'approved' external users.

Licence Schedule

The licence schedule consists of a number of pagesrelating to every base station site used (one per

page), as well as all mobile and fixed equipmentused within each brigade. The detail containedwithin the schedule relates to the technical parame-ters associated with every base station site used bythe brigade and its mobile equipment, and the radiofrequencies the equipment is authorised to use.

Examples are:

Transmit power - The maximum transmittedpower is normally that which enables theuser's operational requirement to be met.This limits the risk of interference to otherusers and allows re-use of channels; and

Height above ground - The height of the aer-ial above ground may have to be limited tothat required to give the required coverage.

Chief Fire Officers who require additional radiofrequencies on any equipment must:

(1) if access to a channel of a neighbouringbrigade is required:

seek the permission of the relevant Chief FireOfficer, forwarding the approval response toRFCPU, for the frequencies and channel tobe included on the schedule; and

(2) if access to any other Home Office managedchannel is required:

obtain written agreement from RFCPU priorto implementation.

Local Authority Chief Fire Officers are authorisedto allow access to VHF and UHF incident channels(used within their Authorities area) by any mem-ber, of any fire brigade, providing assistance withfires in accordance with Section 2 of the FireServices Act 1947 or to secure the discharge of anauthority's function under Section 12 of the Act,subject to the conditions set out in RadioFrequency Policy Statement FPS 16.

Interference to Home Office FrequencyAssignments

The Home Office allocated radio spectrum is usedexclusively for the assignment of frequencies for use


by emergency services, and other Home Office userradio systems. Thus, co-channel interference on themobile channels is likely to be from another PoliceForce or Fire Brigade, as applicable. The bands usedfor VHF/UHF links are shared by both Police andFire Brigades and interference could, therefore, befrom either. Other users on a radio channel is one ofthe factors taken into account when assignments aremade. However, during periods of high atmosphericpressure, co-channel interference from other users ata considerable distance may be experienced, due toenhanced radio propagation.

Emergency service radio schemes are often co-sited with other privately operated systems. Someof these prime sites are heavily used, and there is aconsequent high risk of interference betweenschemes due to the generation of intermodulationproducts. Although steps are taken to avoid assign-ing frequencies that may cause interference toexisting channels, the probability of intermodula-tion interference depends largely upon the stan-dard of engineering at the site.

If interference is suspected of being generatedfrom electrical or telecommunications apparatusoperated by another user, the Radio InvestigationService should be informed. The RIS have detailsof all users at each site and are highly experiencedat solving interference problems. The RIS do notnormally levy a charge if the interference is causedby another user. However, if the investigation con-cludes that the interference was caused by a defi-ciency within a Police or Fire Brigade's ownequipment, then a charged may be levied accord-ingly.

Where interference is thought to involve anotherHome Office assigned service, the Home OfficeFrequency Management Group should beinformed immediately. Where no suitable engi-neering solution is possible, consideration will begiven to the reassignment of one of the servicesinvolved.

Air/Ground Communications

The Police are making increasing use of aircraft,both rotary and fixed wing. The Home Office hasaccess to two 25kHz bandwidth air/ground assign-ments in the military band area of highband VHF,

both of which are available for Fire Service co-ordination with the police.

Fire Brigades are authorised to use one VHF sim-plex channel and three UHF simplex channels forair/ground use operating within the Home OfficeUHF band. Two of the UHF channels are con-tained within the 6 UHF 'Fire Incident" channels,namely channel 1 or 6.

Brigades may select Channel 1 or 6 for air/grounduse but not both. The choice of channel adoptedby each brigade MUST BE notified to RFCPU forrecording on the brigade's radio licence. The thirdavailable channel is one allocated to the Policefrom the National UHF Channel Plan. This chan-nel has been agreed by the Association of ChiefPolice Officers (ACPO), primarily to facilitate thesafe landing of other emergency services aircrafton roads.

Brigades may occasionally have a need to commu-nicate from air-to-ground or vice versa utilisingthe Police VHF or UHF channels. Before doing so,prior approval of the relevant Chief Constablemust be obtained.

All equipment (regardless of channels used) in air-craft must comply with the technical parametersand approvals as laid down in Radio FrequencyPolicy Statement FPS 11.

The Home Office RFCPU recognises that for cer-tain 'very specialised' radio equipment, it may notbe practical for manufacturers to submit a produc-tion sample for independent testing. This equip-ment will usually be low powered and produced invery small quantities. The risk of interference toothers is, therefore, considered to be very small.Under these circumstances, approval may begranted for use of the device in Home Office bandswithout the need for independent testing, providedthe manufacturer or supplier submits satisfactorywritten evidence of the performance characteris-tics to RFCPU.

1.4 Home Office CommunicationsAdvisory Panel (HOCAP)

This panel was created as part of the Review ofRadio Communications in the Police and Fire


Service. The recommendations of the review arenow being taken forward in a project known as thePublic Safety Radio Communications Project(PSRCP). HOCAP's role is to provide guidance toPolice Forces and Fire Brigades, to assist them inmaking informed decisions when consideringfuture investment in new radio communicationssystems during the PSRCP development pro-gramme. The principal aim is that this guidanceshould ensure that any expenditure incurred repre-sents good value for money, and that essentialoperational needs continue to be met.

HOCAP's terms of reference are:

To provide guidance on the provision of newor enhanced communications systems forpolice forces and fire brigades until thePSRCP is complete.

To assist brigades in:

(a) achieving value for money;(b) avoiding wasteful investment;(c) maintaining standards;(d) preserving national operating considera-

tions; and(e) maximising radio spectrum efficiency.

To receive regular information from theProject Board on the progress of theDevelopment Programme.

To promote the work of the DevelopmentProgramme and the PSRCP to forces andbrigades.

To maintain, update and circulate GuidanceNotes to forces and brigades.

The membership of HOCAP varies depending onwhich service has requested the meeting and thenature of the subjects to be discussed.Chairmanship of the meetings will be either theHead of Home Office F7 Division or the Head ofRFCPLJ, as appropriate. Other members will be theProject Manager, the Senior Police or Fire ServiceRepresentative, and the Senior TechnicalRepresentative. In addition, Project AssuranceTeam members and specialist staff may be co-opted as necessary.

A series of HOCAP Guidance Notes has been cir-culated to Chief Officers, these are updated fromtime-to-timc and circulated as appropriate.

Site Sharing

Figure I.I Shared Police and Fire Service Site

(Photo: Bedfordshire and Luton Fire & Rescue Service

The Home Office VHF bands are used to supportwide-area coverage schemes using dominantradio sites. Such sites are often shared with otherusers. These may be other Police forces or FireBrigades as well as private users. Often the Policeand Fire Brigade will have several radio channelscovering one part of the operational area. At eachsite, therefore, several transmit and receive fre-quencies from the same and different bands willbe in operation.

The Home Office Frequency Management Group(FMG) offers a free service which can advisePolice forces and Fire Brigades on the frequencycompatibility of site sharing applications. FMGutilises specialist software to predict the spurioussignals that may be generated when several trans-mitters operate on the same site. Some of the spuri-


ous signals may cause interference to co-sited basereceivers or to mobiles which may be close to thesite.

When considering site sharing applications,Communications Officers are strongly advised toseek assistance from their engineering advisors onthe likely wind loading of the additional aerials andthe resultant overall wind load on the mast. Theoverall capacity of the power supply to the site alsoneeds to be assessed. Further advice can be foundin the relevant Policy Statement on site sharing.

Retained Firefighter Alerter Systems

Fire Alerter systems used by Fire Brigades operateon a 25kHz bandwidth FM alerter channel in theVHF highband portion of spectrum.

The Home Office RFCPU allocate the alerter tonesto brigades. The country has been divided intohexagonal cells 50 km across, with each cell beingdivided further into 127 smaller cells with eachsmaller cell being 5 km across. Seven codes areallocated to each smaller cell, making a total of889 codes. Fire stations are allocated codes on thebasis that the minimum reuse distance is 50kms.All equipment must be type approved by RFCPU.

Licences allowing Fire Brigades to operate theabove type of alerting system will be withdrawnafter 31 st December 1998. Thereafter, systems willcomply with MG-4.

MG4 Specification Systems

In 1991 a new alerter system specification wasintroduced, produced to Home Office Specifica-tion MG-4 (Issue 2), which employs a recognisedindustry standard signalling system know as POC-SAG (Post Office Code Standardisation AdvisoryGroup). The transmitters operate at a maximumoutput of 25 Watts Effective Radiated Power(ERP). The system architecture is structured toprovide each brigade with a unique coded address,together with up to 2000 separate address codeswhich may be allocated within the brigade to a sta-tion, a team or individual as required. (RadioFrequency Policy Statement FPS 7 refers)

All MG-4 base station transmitters must complywith the Radiocommunications Agency Specifi-cation MPT 1325 and Home Office SpecificationMG-4 (Issue 2). Base station aerial heights MUSTNOT exceed 10 metres above ground level withoutthe prior approval from RFCPU.



Chapter 2 - Fire Control Centres

The Fire Service Act 1947 Section l(i)(c) requiresFire Authorities to secure the provision of efficientarrangements for dealing with calls for the assis-tance of the Fire Brigade in case of fire and forsummoning members of the Brigade.

To meet this duty, fire authorities usually have acontinuously staffed mobilising and communica-tions centre, equipped with computer basedCommand & Control systems to deal with thereceipt of emergency calls and the alerting anddespatching of fire service resources within itsmobilising area. Although these are considered tobe the 'core' activities of a Control Centre, manyadditional 'non-core' duties are performed by con-trol personnel as stipulated by the Chief FireOfficer/Fire Master.

All emergency communications for the FireService are channelled through the Control Centrewhich acts as a general communications and infor-mation resource for the Fire Brigade. It is usuallyhoused in either a Control Suite at BrigadeHeadquarters or in a purpose built building withinthe County.

A Control Centre is staffed (in shifts to provide 24hour cover) by uniformed professionals who,although employed under different conditions ofservice to Fire Fighters, are an important part ofthe Fire Service.

Secondary and tertiary control systems are alsomaintained to ensure a continuity of service. Thereare no national standards of'efficiency for handlingfire calls but many Chief Officers have set theirown standards which are set out in BrigadeOrders/Service Instructions or their Citizens Charter.

In most cases the Control Suite comprises aControl Centre, training room, offices, equipment

rooms, kitchen/rest-room, store rooms, locker-rooms/toilets, etc. These rooms and facilitiesshould be well designed and within easy access ofthe Control Centre room.

Control personnel performing duties away from theControl Centre may need to be recalled if there is asudden spate of calls, or personnel become busy forother reasons. Easy access from anywhere withinthe suite will enable personnel to respond quickly.

Comprehensive guidance on the design ofControl Centres was issued in DCOL 8/1997 (inScotland as DFM 8/1997) (FRDG Publication2/97). This is an updated version of Volume 5 ofthe Home Office Guidance usually referred to as'Logica'.

The document includes advice on the ControlCentre design & ergonomics, procurement andlegislation.

The recommended Control Centre rank struc-ture is:

Fire Control Operator FCOpLeading Fire Control Operator LFCOpSenior Fire Control Operator SFCOpFire Control Officer FCOGroup Fire Control Officer GFCOPrincipal Fire Control Officer PFCO

Not all these ranks are represented in every Brigade.

2.1 Basic Call Handling Procedures

The primary function of a Control Centre is toprovide the essential communication link whichenables the provision of emergency firefighting,rescue and humanitarian services to the publicwhen they call for assistance.


Figure 2.1 FireControl Centre.{Photo: Counts' Durham and

Darlington Fire ami Rescue

Service)

The basic principles of running a Control Centrehave a common theme. However, the responsibili-ties and accountability of each rank may varydepending upon the size of the brigade.

The detailed procedures for handling an emer-gency call differ in each brigade according to itssize and the type of communications and mobilis-ing systems used.

Fire Control Operators are trained to elicit infor-mation from those calling for assistance. Thisactivity requires the identification of the incidentaddress and confirmation of the type of emergencyfor which assistance is required.

Difficulties in obtaining this information mayresult if the caller is unduly anxious or excited. AFire Control Operator will still need to bear inmind the primary purpose is to obtain informationand will need to use effective call handling skills toovercome these difficulties, possibly by calmingand reassuring the caller. It may be necessary togive advice for dealing with the emergency whilstwaiting for fire service attendance.

Techniques used to achieve this could include asympathetic approach or perhaps, the adoption ofan authoritative tone. The exact style being depen-dent upon the Operator's perception of what isappropriate in the circumstances.

It is possible that the caller may be in some per-sonal danger. It is easy to understand that such cir-cumstances might create a wide range of behav-ioural responses on the part of the caller.

Traditionally, Fire Control Operators are taughtthe appropriate inter-personal skills by a combina-tion of initial training including simulation exer-cises and 'on the job' training by experienced per-sonnel.

The first contact an emergency caller has with theFire Service is with the Fire Control Operator. Theway the operator handles the call is vital and tothis end the operator must be immediately avail-able to take control of the call. This will enableeffective collation of call details to mobilise, andwill indicate to the caller that they are being dealtwith efficiently.

Further information on the training of ControlCentre personnel is given in the TrainingSection (Appendix I).

The responsibilities of each rank within ControlCentres vary from Brigade to Brigade andmany of them overlap.

The following list gives examples of skills andresponsibilities within each rank.


Control Operator (Core Skills)

Receive emergency calls.

Give advice to emergency callers as required.

Identify and dispatch appropriate fire brigaderesources to incidents, (if necessary receivingguidance from senior ranks).

Be familiar with the location of fire stationsand their station ground.

Keep officers informed of incidents/occur-rences as required.

Liaise with other authorities and resources tokeep them informed of incidents and requesttheir assistance if necessary.

Answer radio messages, relay radio messagesto appliances and officers and act on infor-mation obtained.

Deputise for Leading Fire Control Operatorsin their absence, subject to Brigade require-ments and competence of the Operator.

Test and inspect equipment held in control,and the secondary control, carrying out suchfirst line maintenance as appropriate.

Answer non-emergency switchboard calls outof office hours and direct/advise callers.

Answer non-emergency calls from stationpersonnel and act on information received.

Complete incident statistics.

Work as part of a team and react appropriate-ly as instructed and directed by officers.

Ensure that levels of personal conduct aremaintained in accordance with the standardsprescribed in the Fire Service (Discipline)Regulations 1985 and by accepted ServiceProcedures.

Ensure compliance with current Health andSafety Legislation, including Display Screen

Regulations 1992.

Comply with the Brigade's EqualOpportunities Policy and other relevant legis-lation at all times.

Undertake control/watch administrationduties as required.

Leading Fire Control Operator

Duties mirror those of a Fire ControlOperator with the addition of supervisoryduties.

Assist and support other officers and beresponsible to the Watch Officer in respect ofthe day-to-day, management of the Controlcentre and development of personnel.

Deputise for a Senior Fire Control Operatorin their absence.

Assume duties as Watch Officer in theabsence of a Senior Fire Control Operatorand/or Fire Control Officer, subject toBrigade requirements and suitability of theLeading Fire Control Operator.

Participate in the design, programming, run-ning and monitoring of training programmes.

Provide support and guidance to probationaryFire Control Operators and personnel prepar-ing for examinations.

Be familiar with the general command princi-ples necessary to undertake the variety ofother such tasks and duties as may berequired, to meet the needs of the Brigade.

Senior Fire Control Operator

The tasks listed below may be the responsibility ofa L/FCOp in Brigades that have S/FCOp's asWatch Officers.

In addition to the L/FCOp duties:

Take charge of Command and Control activi-ties during the absence of the Watch Officer.


Assist and support the Watch Officer inrespect of the day-to-day management anddevelopment of personnel.

Ensure that all resources have been dis-patched correctly.

Prepare and carry out watch training pro-gramme, and maintain training records asrequired by the Fire Control Officer.

Undertake administrative/project work asrequired and assist in the supervision andcompletion of Control/Watch administrativeworkloads.

Fire Control Officer

In addition to the above:

Monitor emergency calls and take commandof the dispatch of all resources.

Ensure that fire cover is maintained through-out Brigade area, utilising resources fromneighbouring Fire Brigades if necessary.

Ensure compliance with all BrigadeInstructions, policies and guidelines.

Identify training needs and manage thedesign, programming, running and monitor-ing of training.

Management of Control/Watch administra-tion duties including financial responsibilitiesas required.

Assist and support other officers and beresponsible to the Group Fire ControlOfficer (if applicable) in respect of the dayto day management and development of per-sonnel.

This may include conditions of service, sick-ness monitoring and welfare issues.

Assist and support management in the devel-opment and planning of mobilising strategy.

Group Fire Control Officer

In some cases an FCO or GFCO may also holdother references within the Brigade. These mayinclude Personnel Officer, CommunicationsOfficer or, for example, in larger brigades theWatch Officers may hold the rank of GFCO.

The tasks listed below may be the responsibility ofan FCO in a brigade which does not employ aGFCO:

Responsible for the overall management ofthe Control Centre, its personnel, equipmentand all other resources to ensure the effective,economic and efficient operation of theControl Centre, in line with Brigade policiesand procedures.

Attend control during a major incident orspate conditions, and take strategic commandand provide support as appropriate.

Keep Control personnel informed of Brigadepolicies, procedures and standards.

Monitor the welfare and motivation of per-sonnel whilst constantly seeking to promoteand improve teamwork and efficiency.

Establish an effective working relationshipwith Control personnel.

Monitor all Control Centre personnel inrespect of performance, conditions of serviceand training where appropriate.

Development and planning of mobilising pro-cedures.

Development and planning of control/stationcommunication systems.

Maintain an efficient and effective Commandand Control centre within allocated budgetsprovided.


Principal Fire Control Officer

The Principal Fire Control Officer rank is usuallyused in the larger metropolitan brigades and gen-erally performs the same role as FCO/GFCO inmanaging the Control Centre. Other brigades mayintroduce the rank to lead special projects or behead of section for the Centre i.e.,Command/Control/Communications and IT, orperhaps perform the management function of a DOwith responsibilities for Personnel &Development, Equal Opportunities or Health &

However, in some Brigades the PFCO may beresponsible for developing brigade mobilising pol-icy as part of the Principal Management Team.

2.2 Control Centre Staffing Levels

Her Majesty's Fire Service Inspectorate (and theScottish Office Fire Service Inspectorate) ischarged with the duty of obtaining information onhow fire authorities are performing their functions,with particular regard to efficiency and effective-ness. Included in these functions are the brigadeControl Centre and the manner in which it isstaffed and operates.

To assist HM Inspectors and brigades in settingstaffing levels within the Control Centre, aStaffing Model has been developed. This modelwas issued to brigades as DCOL 6/1996 (inScotland as DFM 6/1996).

The model is designed to give an indicator of thenumber of operators required to handle andprocess a given workload to a given Grade ofService. The model is not intended to take intoaccount levels of supervision, sickness, training orcontrol personnel required for projects, etc. It isused as a means of determining the number ofoperators required, from which decisions regard-ing establishment and officer levels can be made.

HM Inspectors will also use the model to assessthe adequacy of brigade staffing requirements.

Brigade managers are, of course, free to run thestaffing model within their own brigades. However,the Home Office recommends liaison with HM

Fire Service Inspectorate to ensure correct interpre-tation and to develop a common approach.

HM Fire Service Inspectorate does not currentlyrecommend a Grade of Service but may do so inthe future.

Additionally, Fire Service Circular October 1975recommends rank levels for control personnelestablished by reference to the population withinthe Brigade area.



Chapter 3 - A brief history of the'Fire Control Centre'In 1997 the Fire Service as we know it was 50years old, over those years a new career hasevolved; that of Fire Control Operator.

In the very early days strategic mobilising to fireswas virtually non-existent. During the 1800s,numerous fire insurance companies formed theirwon brigades of 'watermen'. Following a call to'fire', sometimes several of these InsuranceBrigades would send their 'engines' and, onarrival, would look for the 'fire mark' to establishwhether the victim was insured and by whichcompany. In the free for all that ensued, thebrigades could find themselves working againsteach other instead of working for the commongood, to the detriment of the public. There was lit-tle co-ordination of resources or direction of theoverall situation.

Over the next century and a half that was to changesignificantly.

One prime innovation which would start the longhaul to a unified well organised service, was theMetropolitan Fire Brigades Act, 1865. The actcovered the City of London and 'all other Parishesand Places for the Time being within theJurisdiction of the Metropolitan Board of Works'.The Act also stated the need 'for the establishmentof Telegraphic Communication between the sever-al Stations in which their Fire Engines or Firemenare placed, and between any such Stations andother parts of the Metropolis'.

This enabled the receiving and transmitting of loca-tions of fires to all stations connected by the tele-graph system. It was the first indication of mobilis-ing from a source remote from the location of thefire and, by necessity, carried out by a fireman atthe fire station receiving what was called a 'runningcall'. A situation that exists to the present day.

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Metropolitan Brigades had an advantage over thesmaller rural Brigades by nature of their size andthe population they served. They were far betterequipped financially to exploit the new technologythat appeared, such as a street fire alarms and firedetectors in commercial premises.

In rural areas, private telephones were scarce andpublic telephones were not as plentiful or well sit-uated as they are today, and there were no streetfire alarms. The firemen in rural brigades wereusually part timers who would rely on being calledby a 'knocker up' or by the sirens that wereinstalled during the First World War. These sirenswere still in use well into the 1970s.

With war approaching, the government mounted arecruitment campaign to encourage men andwomen to join the Auxiliary Fire Service (AFS).Women were encouraged to join as drivers, or towork in fire stations doing office work or watch-room duties. Some women opted for motorcycletraining and driving lessons, while the majoritylearned watchroom procedures and the vitalprocess of mobilising appliances. They all hadbasic firefighting training. (The AFS became theNational Fire Service approximately one year afterthe war started. It was reformed in 1947 to rununtil the mid sixties.)

One of the difficulties of forming a large numberof small brigades into a National Fire Service wasthat most of the equipment, hose couplings, pumpdeliveries and appliances, etc., were all different.This caused obvious problems when one brigadewas called to assist another. There was a desperateneed for standardisation.

All emergency calls were received at the localGeneral Post Office (GPO) Telephone exchange,(at this time telephone exchanges only covered a


Figures 3.1 and 3.2 Posters used during a recruiting campaign in World War II.

small area and there were a great number of them),and passed to the Wholetime fire station in thatarea where a 'Watchroom' was continuouslymanned, either by a firemen, firewomen or a com-bination of both.

After the Second World War, communication wasstill a laborious and lengthy process. Watchroomsor Control Rooms in various brigades evolved dif-ferently, some were staffed by firemen who had arota for 'Watchroom' duties while others werestaffed by firewomen who had served in theNational Fire Service. Many of these womenstayed on after the war to become the forerunnersof today's control operators.

In 1947 the Fire Services Act was passed to makefurther provision for fire services in Great Britain'to transfer fire-fighting functions from the


National Fire Service to fire brigades maintainedby the councils of counties'. With brigades underthe auspices of the County Councils the longprocess of standardisation of all equipment contin-ued. This included the amalgamation of some firestation watchrooms into divisional control roomswhich, because County Councils were also respon-sible for the ambulance service, were sometimesshared with ambulance personnel.

Unfortunately, whilst World War Two had pro-duced some well managed and equipped fire con-trol rooms up and down the country under theNFS, these were thought to be too elaborate forcounty brigades, and were dispensed with.

Mobilising was still carried out by the dutywatchroom attendant who would take call details,dispatch the first attendance and, if necessary,

Figure 3.4 London Fire Brigade WirelessControl Room at HQ.( Photo: London Fire Brigade)

Figure 3.5 AFS Fire Women in Watch Room.(Photo: Kent Fire Brigade)

Figure 3.6 GPO Telephone Exchange, late 1960s.Note red lightbulb for 999 calls.(Photo: Hertfordshire Fire and Rescue Service)

Figure 3.7 Kent Fire Brigade Control Room, I960.(Photo: Kent Fire Brigade)

Figure3.8 Control Room using VF System 'A', 1980.

( Photo: Kent Fire Brigade)


Figure 3.3 London Fire Brigade Control Room, 1937.(Photo: London Fire Brigade)

pass the call to a divisional or district control.It was the duty of the watchroom attendant torecord all fire calls, as well as officer andappliance movements, in the 'log book'. In facteverything was meticulously recorded, usually inbeautiful handwriting.

In some cases, Kent for instance. Brigade controlswere responsible for plotting, logging of all callswith associated paper work, fire reports, accidentreports and statistics, but not at any time talking tothe originator of the call.

Improvements in the telephone network had revo-lutionised brigades. The introduction of a radionetwork was the next step towards improvingbrigade-wide communications.

The radio scheme was sometimes shared with thePolice (provided fire control asked 'nicely' and thepolice were not too busy, the scheme would beopened to allow for transmission) or, sometimes, thescheme was shared with another brigade. Police andFire Brigade radio schemes were the responsibilityof the Home Office Communications Branch, laterthe Directorate of Telecommunications, andremained so for many years.

These early systems, although now construed asrelatively primitive, were to further enhance thecapabilities of the service. Once each Fire Brigadehad their own private mobile radio networks itbecame more practical to operate the radio fromone location. It was one more step towards a singlecontrol.

Contact with fire stations was made by land lineand 'part timers' or retained firemen were called inby housebells or sirens, alerters for retained fire-fighters were not introduced until 1968.

Control rooms were now capable of reliable con-tact with stations by means of the 'K system' andsubsequently, among others, the VF 'system A' andprivate wires, all of which used land lines. Thesemobilising systems were very reliable but ratherslow, the method used to communicate with thestation or stations required was the human voice,and all turn-out instructions, with additional infor-mation if necessary, were repeated. Mobilisingwas accomplished by checking the pre-determined

attendance (PDA) card for the parish or street todetermine which appliance/s to send before alert-ing the station/s. These cards were kept in large'bins' in the control room and if the brigade usedstreet mobilising there were many hundreds ofcards.

Operators prided themselves on their topographi-cal knowledge and remembering the attendancefor many areas or special risks, only using thePDA cards for confirmation. Fire calls wererecorded by hand on individual incident formsand, in some cases, the old 'log book' was still run-ning!

At this time, nationally, control staff personnelwere a mishmash of backgrounds and experience.Control was thought to be the easy option andmany operators were firemen who were on the rundown to retirement, or sick and on light duties.Some brigades started to employ women becausethey couldn't get men to work shift work for thelow rate of pay. Others, of course, had long estab-lished specialised personnel.

The developing use of computers generally in the1970's inevitably led to thoughts of computerisedmobilising. To have finger tip control of all brigaderesources, PDA's, call logging, statistics and instantrecall of information seemed very exciting. Therewas talk of 'paperless' control rooms! In factbecause of this belief many of the consolesdesigned at that time had no 'working' space. Thismistake was rectified next time around.

In 1972 two new courses were introduced at theFire Service College, one was for Communi-cations Officers, a post usually occupied by anoperational fire officer, and the other was the veryfirst course especially for Control Room staff, aSupervisory Officer's course. By 1974, in part dueto Local Government reorganisation, the conceptof a central control room for each County was wellestablished. This was also the year in which LocalArea Health Authorities were formed and FireBrigades and the Ambulance Service went theirseparate ways.

1975 saw the standardisation of Control staff rankstructure and markings, and recruiting was gearedto the special skills required of an operator.


Grampian Fire Brigade was the first to use com-puter aided dispatch, closely followed by GreaterManchester Fire Brigade who went live with afully computerised Ferranti Argos system in 1979.By the late 1980's almost all of the Fire Brigadesin the United Kingdom had a computerised mobil-ising system although some were more sophisti-cated than others.

The number of emergency calls is increasing yearby year, as is the type of emergency. To reflect thediverse nature of fires and special services theynow attended, many Fire Brigades have changedtheir title to 'Fire and Rescue Service'.

The Home Office Guide to Fire BrigadeMobilising Systems, known as the 'Logica' report,was published in 1990 to help Brigades with thespecification, procurement and support of theirsecond generation mobilising and communicationsystems.

Long gone are the days when all that was requiredof the watchroom attendant was to wind a handlefor the station to turn out to a fire and hope thatcontact was made. The requirements and expecta-tions of the control room has changed, and theimprovements in communications have enabled afaster and more effective response.

Nowadays local knowledge is not enough, eventhe most experienced Control Centre Operatorcould not retain the large quantities informationrequired by a modern Fire Service. All incidentsand relevant information are logged and stored onthe database of modern computerised mobilisingsystems.

An operator now requires keyboard skills and aknowledge of computers: retrieval and statisticalsystems: chemical and hazardous material,Management Information Systems (MIS): map-ping systems and most importantly, call handlingtechniques.

An operator also needs to have a basic understand-ing of the many communication systems, be theyvoice or data, that are used in the fire service. Infact it is becoming increasingly difficult to distin-guish between Communications, Mobilising andIT systems.

The Control Centre as the name implies is, by itsvery nature, an essential part of any Fire andRescue Service. Instead of the free for all of theearly days, firefighters can rely on being wellinformed about the incident they are attending,being kept up to date with all developments as theyoccur, and have the knowledge that requests forhelp or assistance will be quickly and efficientlyacted upon.

The skill of the operational firefighter togetherwith the professionalism of their colleagues in theControl Centre, combine to provide an efficientand effective service to the public.



Chapter 4 - T h e 999/112emergency service

4.1 BT

The Public Telecommunications Operators (PTOs)are obliged, under the terms of their licences, toprovide a public emergency call service by meansof which any member of the public may, withoutcharge, communicate as quickly as practicablewith any of the appropriate local emergencyauthorities (EAs) to notify them of an emergency.

The 999 call service provides national coverage inrespect of the four main emergency services, i.e.,police, ambulance, fire and coastguards. Other ser-vices can also receive emergency calls via thepolice. These organisations are cave rescue, col-liery rescue, mountain rescue, air/sea rescue, diveremergency and cardiac units.

BT takes approximately 21 million calls eachyear, including 2 million mobile 999's and callsfrom cable networks. Cable & Wireless (formerlyMercury) take 2.8 million including mobile andcable company calls, whilst KingstonCommunication handles 200,000 calls. Requestsfor police help account for some 55 per cent ofemergency calls, while the ambulance serviceaccounts for 33 per cent and the fire brigades forthe majority of the remaining 12 per cent. Some 50per cent of all 999 calls are false calls, wherecallers make no request for an EA, and are safelyfiltered by BT and Cable & Wireless operators atthe request of the EAs using agreed procedures.

4.1.1 The British Telecom fixed telephonesystem

There are fifteen BT Operator Assistance Centres(OAC), these are at Aldershot, Aylesbury, Bangor,Belfast, Blackburn, Bristol, Cambridge, Glasgow,Hastings, Inverness, Leicester, Newcastle,Newport, Thanet and Warrington.

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Communications and Mobilising

Figure 4.1 A BT Operator Assistance Centre.[Photo: BT)

The trunk reservation facility will be used toensure that there will always be at least two cir-cuits reserved for 999/112 calls on a route from adigital local exchange. More importantly, howev-er, this facility allows an additional circuit to bereserved for a 999/112 call each time an existingcircuit is taken into use for a 999/112 call. All ofthe circuits in a route are thus, potentially, avail-able for emergency use. This gives protection indisaster situations which cause a sudden surge of999/112 calls.

If it is not possible to route operator traffic to theprimary operator centre due to congestion or fail-ure within the network or evacuation of anOperator Assistance Centre, 999/112 traffic will berouted to an alternative OAC.

The connection of an emergency call involves fourmain phases:

23

(1) Connection of the caller to the operator viathe 999/112 code;

(2) Selection by the operator of the requiredEmergency Authority Control Centre(EACC);

(3) Onward connection of the caller to theEACC; and

(4) Confirmation that the connection has beenestablished with the appropriate EACC andability to provide further assistance to thecaller or EA when required.

The operator will monitor the call until the callerhas passed their location and is clearly givingdetails of the incident. The operator normallyholds the call in the system without listening(unless there are difficulties) until both the callerand EA have cleared the line.

It is the responsibility of the EA Control Centrestaff to obtain adequate address informationfrom the caller to enable the EACC to locate theincident being reported.

4.1.2 Operator call-handling procedures

The action of dialling 999/112 on BT's public tele-phone network in the UK automatically routes thecaller through to a designated Operator Centre.Here, if it is not immediately answered, the call isvisually and audibly signalled on all operatingpositions and, in addition, a special red light oper-ates to ensure that the call is given immediateattention by a BT operator.

To cater for unforeseen circumstances EAs have toprovide three separate routes from the OperatorServices Centres to the emergency service. Thesecondary and alternative routes would normallybe used in sequence in the event of an unusuallyhigh level of traffic or a fault on the primary route.

BT will allow a 30 second delay with no replybefore another route is attempted unless the EAcontrol centre has a call queuing system, in whichcase additional time is allowed. For this reason it isvital to inform BT if any call queuing system isinstalled.

These routes are:

PrimaryThis is the route that the PTO operator willinitially use to connect a caller to the EACCand the EA must provide sufficient capacityon this route to handle normal 999/112 traffic-distribution.

EAs will reserve primary routes exclusivelyfor receiving 999/112 calls.

SecondaryIn circumstances where the PTO operatorreceives no replyon the primary number after30 seconds, the operator will connect the callto a secondary number provided by the EA,except where call queuing is used. This pro-cedure should only be necessary in instanceswhen the EACC has an unusually high levelof traffic or a fault in its switchboard or oneof the PTOs' networks.

AlternativeIn the event of a major problem which resultsin the primary and secondary routes to anEACC being unavailable to the PTOs, the EAshould provide the PTOs with an alternativemeans of taking delivery of the call, ideally ata different EACC for maximum security.

To provide adequate security, this alternativenumber must be served by a different net-work route from that providing the primaryand secondary routes. EAs would have toconsider, where appropriate, which EAControl Centres are used as alternatives toeach other.

These routes are agreed between the EA and theBT Emergencies Services Manager. Changesarranged by EAs have to be notified directly tothe ESM giving at least two weeks notice.

All the routes have to be staffed on a 24 hourbasis.

When a PTO operator answers an emergency callthat has originated from a digital exchange, the fullnational calling line identity number (CLI) will beautomatically displayed on the operator's VDU.


Figure 4.2 BT emergency call handling system.(Diagram: BT)

This removes the necessity for an engineeringtrace to identify the calling line if the caller isunable to provide this information.

The CLI number uses a different mechanism toBT's Caller Display and Call Return (1471) ser-vice. The number cannot be altered or withheldby the caller.

Prior to all the PTOs completing their digital net-works, calls originating from an analogueexchange will not show the full telephone number,though a partial display of the exchange code maysometimes be obtained. The customer may there-fore still need to be asked for their number in orderto route the call correctly.

The originating calling information (CLI) will beused to automatically display details of the appro-priate EACC connect-to numbers.

It is worth noting that an increasing number ofbusiness customers have DDI systems and/or pri-

vate networks. In these cases, the number automat-ically presented to the PTO operator is usually theoutgoing number of the main switchboard. Thiswill be the number passed to the EA and may bedifferent to the number the caller may give if askedby either the PTO or EA operator.

There are also some private networks that extendover several areas. Their 999/1 12 calls could befed into the PTO networks in only one of theseareas. This will lead to inevitable problems as theywill be presented with a telephone number applic-able to this area and, therefore, routed according-ly. These will only become apparent at the EACCwhen the caller is questioned as to their location.

The operator establishes which EmergencyAuthority is required by answering the call with'Emergency, which service?'

If the caller needs to be asked for their number thisis entered onto the screen.


The operator hands the call over by passing theOperator Assistance Centre (OAC) name and thecaller's number and listens while the caller passestheir location. If this has been given clearly and thecall is progressing, the call will be held in the oper-ator's system (without listening) until the call iscomplete. Operators normally listen throughout indifficult cases, for example, panicking callers orwhere there is a language problem.

If it is necessary to speak to the BT operator againit should be possible to call them back onto the linewhile the call is being listened to. At this stage ofthe call there are two options to speak to the BToperator.

(1) Operators can normally see when the callerand the EACC have cleared. If the EACC hasthe necessary facilities it is possible for EAoperators to cause the word 'Flash' to appearon the BT screen.

(2) The operator may be alerted by failure to clearthe line, although this may take some time ifthe operator is dealing with another call.

If details of the call are required once the call hasbeen released, it will be necessary to dial the OperatorAssistance Centre number allocated to each Brigade.The allocated number should be used even if thecall was passed via a different OAC.

Every emergency call is recorded both on magnet-ic tape and on a call printout which shows basiccall details, such as time, telephone number andaddress of the call. BT's recording of emergencycalls is from the time that the call is answered bythe BT operator to the time when the call to the EAis cleared by the caller and the EA, the speech ofall parties is recorded. All 999/112 call records areheld for three months.

4.1.3 Mismatches between EA and FixedNetwork Operator Boundaries

BT has over 7500 exchanges, each with its owncode, it is these codes that determine how the callis routed. BT exchanges have grown up over thelast 90 years as the cable network has evolved andeach has a defined catchment area averaging 4kmin radius.

Exchange area boundaries do not always coincidewith EA boundaries. Where 'mismatches' exist,careful planning and general agreement betweenneighbouring Chief Fire Officers/Fire Masters andthe BT Emergency Services manager has to bereached on which EA Control Centre will take thecalls from the whole of the split exchange area inquestion.

The Fixed Network Operators will connect alldirectly connected customers to the appropriateEACC for the agreed geographical areas whereverpossible. It will be the EA's responsibility to passinformation if necessary to another EACC in thesemismatches cases.

4.1.4 Provision of ex-directoryinformation

BT operators will only provide name and addressinformation for numbers from which a recent999/112 call has been made. All other routinerequests for such information must be made byEAs through BT's Network Special InvestigationsGroup.

In providing an XD/NC service BT undertakes notto give the number to anyone outside BT includingEAs. BT has laid down procedures to enableurgent calls to be connected to XD/NC customerswithout revealing the number. EAs requiring sucha connection must contact BT OACs using 100service where the operator will ask a number ofquestions to support the request before connecting.

4.1.5 Access to tape recordings ofEmergency Calls

BT will record all calls terminating on 999/112 cir-cuits. Calls are recorded from the time the call isanswered by a BT operator until the EA and callerclear the line, and the circuit is released.

Requests from EAs to listen to, to make notesabout, or be given a copy of a recording of a999/112 call must be referred to the BT NetworkSpecial Investigations Group.

These requests must be authorised by the agreedlevel according to the Code of Practice whichstates:


Access to emergency call records can be obtainedin two forms:

Normal For investigatory purposes where it isrequired as evidence or similar use.Arrangements for access will be agreedat the time of request.

Urgent Where instant access is required torespond to a 999 incident. (Currentequipment means this would take sever-al minutes.)

The authority levels for access required are:

Normal Duty Principal Officer

Urgent Senior Duty Control Room Officer

An authorised representative of the EA (not neces-sarily the Authorising Officer) must be presentwhen the tapes are being played at an OperatorServices Centre.

BT will only keep original 999/112 recording tapesfor a period of 3 months. Evidential quality copiescan be requested if necessary.

BT will apply to the Chief Officer of the relevantEA for similar recordings of calls made by theEAs.

PTO's inform all their customers to use the999/112 code when making emergency calls.PTO's do not tape record emergency calls made onany other circuit. However, such calls areprocessed despite the use of the incorrect code.

4.1.6 Calling Line Identity (CLI)

Since 1985 BT have been modernising their net-work and converting from analogue to digitalexchanges. This modernisation is almost completegiving 99% CLI coverage, which means BT oper-ators have instant access to the callers address on40 million lines.

Once BT developed CLI for their own operators,the emergency services requested an enhancementto 999 services to reduce call handling times andthe number of hoax calls. Their requirement was

an enhancement which would allow the telephonenumber and address of the caller to be automati-cally displayed on the EAs own mobilising com-puter screen.

The advantages of CLI are:

Caller's number and address automaticallyavailable on answer, no need for informationto be passed verbally or the EA operator totype. Reduces typing errors.

Name of BT OAC displayed, for call back ifnecessary.

Caller can speak to the EA sooner, reducingfrustration or panic. Address and telephonenumber is simply confirmed.

CLI overcomes the problem of spelling, pro-nunciation and language difficulties.

Early indication of hoax calls - the auto-address will reveal if the caller is giving afalse address or at a payphone often used tomake malicious calls, or perhaps a mentalhospital.

As mobile zones decrease in size the auto-matic Zone Code may help EAs to questioncallers who are unsure of their location.

BT have devised a system which requires an ISDNlink from that operator centre which is used to for-ward CLI to the EACC. On receipt of a call theEAs mobilising system will dial into the BT data-base for address information which will be dis-played on the EA mobilising screen, this will takeless than 10 seconds, (a pilot trial in place at thistime is providing the information in one second).This is technically a dial-up system (which willhave a small cost implication for the EA) but willappear automatically to the EA operator.

Trials of this system have commenced in theAmbulance service and will shortly commence forthe Police. The Fire Service (CACFOA) havedecided to wait for the long term strategic solution,when, once European Standards have been devel-oped, should allow CLI name/address to be passedtogether.


The trials assess:

The performance of the technical solution.

Processes such as audit trails.

The most cost effective packages for rollout.

Savings in time to despatch (EA).

Reduction in call handling times (BT and EA).

The results of these trials will give BT informationwhich will be used for the long term solution whenthe European standard is agreed.

Whichever system is used, it will only be possibleto automatically obtain the telephone number andaddress of the caller if they have dialled 999 or112. The system design dictates that these calls fol-low a certain technological route which safeguardsthe integrity of the BT system.

It will not be possible for any EA to type in anumber and interrogate the BT database. Bythe act of dialling 999/112 it is deemed a caller hasgiven consent for this information to be used and,therefore, complies with the Data Protection laws.

Although in most cases the emergency call ismade from the address of the fire, it should notbe assumed that this is so. Experienced EA opera-tors will recognise the dangers and know how easyit is to get an affirmative answer to any question.

Training on call handling procedures will have toreflect this.

4.1.7 Network Resilience

In the event of a major failure to a part of a PTO'snetwork, the PTO will notify the affected EAs assoon as possible after the failure is identified, or isanticipated.

The process for informing EA's of any BTexchange that fails to give customers 999 accesscommences when a regional Network OperationsUnit (NOU) detects a failure that causes loss of999 access. Once the extent of the problem isknown a report of the failure is faxed to each


appropriate EA Control Centre (Police, Fire,Ambulance and Coastguard). In addition theNetwork Operations Unit draws attention to thefax by telephoning the Police control, which inturn telephones the other affected EAs. If neces-sary, progress reports are faxed at periodic inter-vals and finally a fault clearance report is sent once999 access has been restored. The process includesthe provision by BT to the EAs of maps showingthe area covered by each of its exchanges.

EAs and relevant PTOs should prepare localcontingency arrangements to cover the receiptof emergency calls during conditions of seriousbreakdown in the PTO network.

4.1.8 Priority Fault Repair Service

The conditions in the PTO's licence requires them toprovide a free Priority Fault Repair Service to thoseemergency authorities who receive 999/112 calls onlines connected to the PTO's network. When notifiedof any fault or failure which causes interruption, sus-pension or restriction of the telecommunication ser-vices provided by the PTO, the PTO will restorethose services as swiftly as practicable and with apriority, so far as is reasonably practical, over FaultRepair Services to other persons.

Where an EACC has connection directly to a PTOfor an Emergency Call Service, Priority FaultRepair Service will be extended to all 999/112 cir-cuits in accordance with the relevant condition ofthe PTO's licence. This is Condition 9 of the Cable& Wireless licence and Condition 10 of the BTlicence.

The BT Priority Fault Repair Service will applywhere BT and Cable & Wireless use common ter-minations supplied by BT.

4.1.9 BT National Emergency Linkline

The National Emergency Linkline is a servicedesigned to give nominated customers a quick andeasy means of contacting BT to request assistanceduring emergency situations.

Nominated customers are primarily the Emer-gency Services and Local Government, as theywould normally be responsible for co-ordinating

emergency incidents. However, the service can bemade available to Health Authorities, the ArmedForces and those public utilities that are likely toplay a significant role in major emergencies.

This service has been specifically set up for use inthe event of Civil Emergencies and major disas-ters. It is NOT for normal business enquiries.

BT's modern digital technology uses a flexible callrouting tool known as Advanced Linkline Services.This facility can direct calls from a special nation-al telephone number to one or more pre-selectedanswering points. The National EmergencyLinkline number dialled from anywhere in the UK,connects the caller to the nearest EmergencyLinkline reception point, normally the local BTNetwork Operations Unit. The NOU will ensurethat a request for assistance is handled promptlyand that all necessary parts of BT are alerted.

The service is available 24 hours a day.

When requesting assistance a caller must identifythemself and the organisation that they representand provide a telephone number on which they, oranother representative, can be contacted. Theyshould give as much detail about the incident aspossible to enable BT to react quickly.

The information should include:

Accurate location (e.g. address/grid reference).

Casualty situation (e.g. is an enquiry bureaubeing set up?).

Access problems (e.g. difficult terrain orparking restrictions).

On-site security (e.g. will BT identity cardssuffice?).

Reporting instructions (e.g. who should BTpeople report to?).

Communication needs (e.g. requirements atthe scene/incident control?).

Safety issues (e.g. are there any hazardousconditions to consider?).

The National Emergency Linkline numbermust not be disclosed outside the organisation.This will ensure the service is not abused by unau-thorised users.

To get more information (including the NationalEmergency Linkline number) contact the local BTZone Emergency Manager.

4.1.10 (Government Telephone PreferenceScheme

The Government Telephone Preference Scheme(GTPS) provides a contingency facility for the with-drawal of outgoing telephone services from themajority of customers on a telephone exchange. Thescheme is designed for use in a serious crisis whenincreased use of the telephone network is causingsevere congestion and preventing the emergency ser-vices and other essential users from making andreceiving calls. At present the scheme only applies toBT and Cable and Wireless.

Lines that have their outgoing service withdrawnunder the scheme will retain the capability ofreceiving incoming calls. Normal service will berestored to all customers as soon as possible.

Rules for the selection of lines for inclusion in thescheme have been set by Government. These rulesand other information about the scheme are con-tained in a Government Notice.

The GTPS can only be invoked by the govern-ment in exceptional circumstances. However,the facilities it provides can be used by BT orCable and Wireless as part of their network man-agement arrangements if their network is heavilyoverloaded or damaged.

The scheme only operates over PSTN lines. Thereis no charge for this service.

All exchange connections are placed in threecategories.

Category 1 consists of those lines essential toGovernment and the emergencyauthorities in a severe crisis oremergency which is affecting thepublic telephone network.


Category 2 includes lines additional toCategory 1 that are required tomaintain the life of a communityduring civil emergency.

Category 3 covers the remaining lines not enti-tled to special preference during anemergency.

All Government departments have a designatedauthority to nominate for inclusion in Categories 1and 2, this process is known as 'sponsoring'.Sponsors are required to notify BT or Cableand Wireless annually of the lines they wish tonominate for inclusion in (JTPS. The GTPSadministration is handled by BT and Cable andWireless Emergency Planning Managers.

4.1.11 Secondary Control

As well as providing PTO's with secondary andalternative numbers, Fire Brigades should havealternative arrangements to cover the receipt ofemergency fire calls during conditions of seriousbreakdown, either in BT's network or their ownbrigade communications systems.

These arrangements usually involve a 'secondarycontrol' set up either in a different building on thesame site or at a different location. Considerationalso has to be given to the receipt of calls duringthe interim period, EAs should make use of auto-matic call diversion facilities where possible.

Managers of Control Centres which normallyreceive emergency fire calls should run exercisesperiodically to ensure that all staff are familiarwith the contingency arrangements.

4.1.12 Publicity/ Public Education

The Public Telecommunications Operators and theEmergency Services continue to be activelyinvolved in various education programmes aimedat young school children.

Apart from the Strategic Framework for CombatingMalicious Hoax 999 Calls (DCOL9/96), many sep-arate initiatives have been taken by the PTO's,Police, Fire and Ambulance services to educate thepublic as well as reduce the number of hoax calls.

It is interesting to note that the Coastguard receivevery few malicious or hoax calls.

Education and advice to the public is ongoing, andwill become more important if the Police andAmbulance services introduce 'second priority'numbers for minor emergencies.

HM Fire Service Inspectorate and CACFOAadvise against Fire Services using a 'minor emer-gency' number.

It is not generally recommended that personsshould call the fire brigade by dialling the fire sta-tion or the fire control number direct, and the rea-sons for this are as follows:

Directly dialled calls cannot be monitored bythe BT operator.

It is seldom possible to trace the origin of adirectly dialled call.

The call would be delayed if the fire brigadenumber were found to be engaged or out oforder.

Payphone users would need to insert coinswhich, in an emergency, might not be readilyavailable.

Entries in telephone books

A standard page is included in the preface of all tele-phone books on the use of the 999/112 emergencyservice. Administrative telephone numbers of firebrigade headquarters and other departments or estab-lishments should be inserted in telephone booksunder the heading of the local authority concerned.

4.2 Cable & Wireless 999 service(Formerly Mercury Communications)

Cable & Wireless work within the Code ofPractice for The Public Emergency Call Servicebetween Fixed Network Operators and theEmergency Services.

In February 1997 Cable & Wireless outsourced themanagement of their Operator Services to a com-pany called EXCELL Multimedia Services Ltd. As


well as handling all 999 calls, Operator serviceshandle Operator 100 and International OperatorServices. Any query or problem with the 999 ser-vice should be referred to Cable & Wireless.

Cable & Wireless handle approximately 2.8 mil-lion 999 calls each year. It provides service to itsdirectly connected customers and to the customersof a number of Other Licensed Operators includ-ing (but not exclusively) cable carriers and mobilenetworks. The Emergency Service operators arelocated in two call centres in Birmingham and onein Glasgow which handle all 999 and 112 trafficoriginating or connecting onto the Cable &Wireless network anywhere in the UK.

These call centres are fully resilient being on sep-arate power supply lines with separate multipleconnections to the Cable & Wireless trunk net-work. The sites have on-site emergency powergenerator provision. They share the same manage-ment and ancillary structure.

999 and 112 calls entering or originating on theCable & Wireless network are routed by the short-est possible route to one of five dedicated switch-es for Operator Services traffic, located around thecountry. These switches form a complete resilient,fully networked five-node system for routing traf-fic to the Operators. The system has full 24 hoursupport and queues have Real Time ManagementInformation Systems to ensure all calls areanswered immediately. The system is configuredto give these calls priority over all other traffic onthe Cable & Wireless network.

The emergency operators in the Birmingham callcentres connect callers to the Emergency Service.For reasons of cost and speed the call will routeover the Cable & Wireless network emerging, ifnecessary, onto the BT network at the nearest PointOf Interconnect to the Emergency Authority. At notime are BT 999 operators involved in Cable &Wireless 999 procedures, only BT's local networkwhere required by the Emergency Services owntelephone network.

4.2.1 Operator call-handling procedure

When a directly connected, One2One or Cable cus-tomer dials 999/112, an Emergency call attempt

will be recorded within the call centre by means ofan audible and visual signal. The call is immediate-ly given the highest priority. The operator holds anyexisting call on the console and answers the emer-gency call "Emergency, which service please?".

Simultaneously, the operator will have received adisplay of the 'calling line identity' - originatingcallers telephone number, in addition to which,automatic voice recording is activated. If the callhas originated from a cellular caller a 5 digit areazone code will also be presented.

At this time, the operator will initiate a search ofthe customer records database (Front OfficeDirectory (FRNT)), using the displayed callingline identity and/or zone code. If the search is com-pleted successfully, the operator will have the fol-lowing customer details displayed:

Caller's telephone number.

Name.

Address.

Primary connect - to numbers of eachEmergency Service.

Secondary connect - to numbers of eachEmergency Service.

(Where zone code is used, callers name and tele-phone number will not be available.)

Where callers details cannot be retrieved fromFRNT, then the operator will refer to a 'backup'screen on FRNT which will provide the relevantconnect-to numbers in accordance with the callersSTD code presented in the calling line identity orcellular callers given county location.

If the caller is dialling from a company site, theoperator will ask the caller to confirm their tele-phone number. By doing this the operator willhave access to a direct dial extension line withinthe site. The calling line identity will often onlydisplay as a main switchboard number of the site.

The operator will advise the caller that they arebeing connected to the requested Emergency

Communication* and Mobilising 31

Service. Once connected and an answer from theEmergency Service is gained, the Operator willintroduce the caller by announcing:

Operator call centre identification;

Customer's calling line identity; or

Direct line number, provided by businesscaller.

Once these details are given, the Operator willhold the call on the console, and leave the call inprogress, allowing the Operator to become avail-able to answer other incoming 999/112 calls. TheOperator will only remain on line if requested todo so by the Emergency Service.

Once the operator has left a conversation inprogress between the Emergency Service and thecaller, the console will visually display the call sta-tus. When the call is complete, and all parties havecleared the call, the Operator can relinquish thecall. At this point, a call print out will be generat-ed, providing the following details of the call:

Date.

Relinquish time.

Operator distribution cabinet number.

Console number.

Operator identity number.

Call type (999/112).

Calling line identity (& zone code whereapplicable).

Number that the call was extended to.

Any operator comments relating to call.

ified police control relevant to the area and adviseof the caller's attempt and any other useful infor-mation e.g., name, address, telephone number.

If during any 999/112 call attempt where caller'sdetails cannot be retrieved from FRNT, then theOperator will contact the Switch Network 'B' divi-sion (SNB) to obtain detailed information.

Where the caller is a subscriber of anotherLicensed Operator, dedicated 'hotline' numbershave been set-up to each operator in order to pro-vide speedy retrieval of information.

Cable & Wireless have no plans at present toautomatically forward CLI information toBrigade mobilising systems.

4.2.2 Enquiries and requests fromEmergency Services

In some instances, an Emergency Service may findit necessary to request additional information or toseek clarification after a call has been released bythe Operator. The Emergency Service must call thedesignated numbers within the centres and advisewhat additional information is required. Therequest will be actioned by a Team Leader orOperator immediately.

Access to emergency call records and recordingsshould be obtained in accordance with the FixedNetwork Code of Practice.

4.3 Kingston Communications

Kingston Communications Ltd are little knownoutside the Hull area but they have run an operatorservices Department since they were established in1904. One of these services is handling any incom-ing emergency calls from anywhere in theKingston Communications network, which is 120square miles in and around the city of Kingston-upon-Hull.

They operate under the Fixed Network CoP andhandle approximately 200,000 calls a year, alloperators are trained to handle emergency calls.Kingston Communications pass calls toHumberside Fire Brigade using the primary, sec-ondary or alternative numbers.


4.4 Telephone Number Portability

Telephone number portability means that sub-scribers can keep their existing number when theychange phone companies.

Portability was proposed by OFTEL to eliminatethe problems and expense (mainly for businesscustomers) of changing a phone number whenchanging from one licensed operator to another.

Agreed procedures between the EmergencyServices and the PTOs (before number portabilitytrials on the fixed networks took place), ensure thatcustomer addresses are always available for use onemergency calls during the transfer.

Licence modifications are now proposed for themobile networks, this means that from January 1st1999 portability will be extended to mobile phones.

The ability to obtain customer record informationon mobile networks will become almost impossible.

Portability will be between mobile and mobile orfixed and fixed networks. There will not be con-vergence between the two systems for the foresee-able future.

4.5 Emergency Text TelephoneService for the deaf

Typetalk - (DCOL 6/ 1995,DFM 5/1995)

The Director General's OFTEL AdvisoryCommittee on Telecommunications for Disabledand Elderly People (DIED advised that allinvolved in the 999 service should take account ofthe need to establish uniform access to the emer-gency services for people with severe speech andhearing difficulties.

To that end the Text Users' Emergency Servicewas launched in March 1995.

Run by Typetalk, which is part of the RNID, andfunded by BT, it gives deaf, deaf and blind, deaf-ened, hard of hearing and speech-impaired peopleaccess to the Emergency Services. A deaf orspeech-impaired person who is unable to use an

Figure 43Emergency texttelephone for thedeaf

(Photo: Typetalk)

Figure 4.4Using a textphone.(Photo: BT)

ordinary telephone uses a textphone, which is likean ordinary phone but has a keyboard and screen,to dial the Typetalk Text Users' EmergencyService on 0800 112 999.

The operators employed by Typetalk are highlytrained and fully familiar with the needs of deafand other text phone users.

Typetalk procedure for dealing with incomingEmergency calls

(1) Receive call on Text Users Emergency Service(TUES) terminal. Emergency calls take priori-ty over all other switchroom activity.

(2) Establish the number from which the call isbeing made.

(3) Establish the service required by the caller.

(4) Attempt to obtain name, address and locationof incident if different from caller's address.


(5) On obtaining minimum information (callingline number and service required) dial out to therequired Emergency Authority using BT 999service and instruct BT to connect Typetalk tothe EA for the calling number given.

(6) On connection with the EA, the Typetalkoperator will relay the call between Textcaller and EA by voice. BT operator will nor-mally remain on line to monitor call and offerassistance with locations, etc.

The text side of all calls is recorded on disk forfuture review/investigation, if necessary.

Departures From Standard Procedure

In the event that Typetalk are not given the callingnumber by the caller, attempts will be made toestablish their location. This allows for connectionof the call to the appropriate EA using the countylists and direct connect-to numbers.

In the event of failed connections, or calls whichgo off-line mid-stream, the back up CLI (CallingLine Identity) printer is used to try and establishthe calling number. Attempts will be made to con-tact the calling number. If contact with the caller isnot successful a call is made via the BT 999 ser-vice to the Police control for the area of the callingnumber to report a failed Emergency Call.

It should be noted that the CLI is not alwaysreceived. It may be suppressed by the caller, or befrom a network which does not share CLI with theBT network.

The service is tested at regular and frequent inter-vals. This testing involves Typetalk and BTresponses, EA's and BT are not informed of thetimes of any test calls.

4.6 Emergency calls from theRailway Industry Network

Since British Rail was fragmented into a numberof different companies and franchises the collec-tive term used is the 'Railway Industry'. The rail-way industry has it's own telephone network - theExtension Trunk Dialling network (ETD) operatedby RACAL-BR Telecommunications Ltd (RBRT).

The ETD network is almost exclusively used by rail-way personnel although, in some circumstances,possibly an emergency situation, it could be usedmembers of the public. Dialling 999/112 from thisnetwork connects the caller to an RBRT Operator,not to a BT Operator Assistance Centre. To avoidany confusion all RBRT phones are clearly marked.

An Emergency Call is defined as a call from anysource, concerning an incident, for which thecaller requests the assistance of any of theEmergency Services. Emergency calls will only beanswered by RBRT Operators who are trained andcertified as competent to do so, all emergency callswill take priority over any other call and actedupon even if it is a repeat call.

There are currently five designated Switchboardswhich would normally receive emergency calls,these are at Crewe, Glasgow, London Waterloo,Swindon, and York.

Emergency calls from any part of the country couldbe received at any of the designated Switchboards.The operator begins by asking which service thecaller requires and the location of the incident.Location details are entered into the TelephoneOperators Directory System (TODS) which willshow the primary and secondary connect-to num-bers of each Emergency Service Control Centre.Emergency calls on this network will almostalways originate from a railway location, althoughit is possible for the switchboard to receive callsfrom non-railway locations. In this situation loca-tional information is unlikely to be found on theTODS database and the RBRT Operator willendeavour to obtain enough information (such asthe nearest town, etc.) to correctly route the call.

If the EA primary number is unobtainable, or notanswered within 30 seconds, the RBRT Operatorwill try the secondary number. If this is notanswered, or is unobtainable, then the call ispassed to the Civil Police. The number given bythe RBRT operator is an ex-directory emergencyringback number.

RBRT will remain on the line until the EA opera-tor has all the required information and the call iscomplete.


All details of emergency calls are recorded on anEmergency Call Record Form which is kept forone year, as well as recorded on audio equipmentand kept for one month.

4.6.1 Payphones

The card payphones situated on trains for publicuse are not part of the ETD network. These 'phonesare GSM 'phones which accept prepaid 'smart'phonecard and credit cards. GSM public payphonesare also installed on some domestic coaches,Scottish and cross channel ferries and Eurostartrains. Phones on the cross channel services havethe added facility of 'roaming' onto the French andBelgium GSM networks.

It should be noted that it is not possible to make999/112 calls from these payphones. The phonesare clearly marked to inform the public that999/112 calls are barred.

4.7 Cellular communications

Cellular radio is a telecommunications servicewhich allows people with mobile phones to makeand receive 'radio' telephone calls within the ser-vice area to and from almost all national, interna-tional and other mobile phone network numbers.

In the early 1980's Government and Industry con-cluded that British business would be handicappedwithout adequate mobile communications. To this endcellular licences have been granted by the Departmentof Trade and Industry (DTI) since June 1985.

The cellular licence issued by the DTI and moni-tored by OFTEL prohibits some network operatorsfrom dealing directly with customers. This has cre-ated a complex multi-tiered market structure com-prising of Service Providers, Dealers and HighStreet Retailers.

This complex structure has implications whentrying to trace an abandoned call on a cellularnetwork.

The original cellular 'phones were analogue but by1997 there were twice as many digital phones asanalogue, many of them utilising 'Global Systemsfor Mobile Communications' (GSM).

The history of GSM started in 1978 at the WorldAdministrative Radio Conference (WARC) wherethe radio frequency band for cellular mobile sys-tems was agreed upon.

In 1982 a committee was set up to ensure that thefrequencies allocated to cellular radio were beingused correctly and to co-ordinate plans for aEuropean standard. This committee was called'Groupe Special Mobile", the European standardhas taken its name from this committee, henceGSM.

In 1987 twelve countries agreed to sign aMemorandum of Understanding to design andimplement GSM. Work on the technical develop-ment of GSM continues through the EuropeanTelecommunications Standard Institute (ETSI). In1990 the GSM initials were changed to representthe new title 'Global Systems for MobileCommunications'.

GSM, now considered an international standard,was developed to ensure compatibility across cel-lular networks, allowing mobile phones to operatein different countries.

GSM means there will be an increasing number ofoverseas customers using their mobiles on UK net-works ('roamers'). 'Roaming' may cause problemsin tracing silent or difficult emergency calls.Although the mobile number will inform theBritish PTO of the caller's country of origin, anytrace can only be done by dialling the caller back.The call will be routed via the country of originwhich has cost implications for EAs and PTOs.Additionally, many 'roamers' have incoming callsbarred because the cost of the call from their coun-try of origin is charged to their own number.

It is unlikely a call from a 'roamer' could betraced. Therefore, it is reasonable to considerthese calls un-traceable.

4.8 Cellular 999 services

The cellular operators 999/112 call service is basedon six northern Operator Assistance Centres(OACs). BT handles all 999/112 phone traffic forCellnet, Vodafone and Orange. One2One emer-gency traffic is handled by Cable & Wireless.


Cellular network companies found several prob-lems that had not been experienced to such adegree with the fixed networks. To help over-come these problems a Code of Practice wasdevised under the auspices of the Home Office999 liaison Committee - The Public EmergencyCall Service (PECS) for Mobile Radio 999Emergency Access.

When a 999/112 call is generated on the cellularnetwork, it is received by the base station provid-ing the strongest signal, generally this will be thenearest cell site to the location of the caller.However, because the transmission is radio, sev-eral conditions may influence where the signaltravels to i.e., local topography, poorly positionedaerials on vehicles, or weather conditions. Alsothe fact that cellular frequencies travel exception-ally well across water add to the contributingfactors.

The incoming call will be transferred to the fixednetwork providers through their OAC's and pre-sented to the Operator by means of a 4 digit zonecode. Zones roughly mirror county boundaries andare used to direct the call to the correct emergencyauthority. The zone code accesses the OAC's data-base and produces the connect-to-number for eachof the emergency services.

Mis-routing of cellular calls generally happensbecause of the reasons stated earlier. It is also notpossible to impose the same boundaries as with aland line system, this is especially apparent in ruralregions where one transmitter may service quite alarge area. With the growth of the Cellular indus-try and zones becoming smaller, the occurrence oflong distance mis-routing is likely to become lesscommon.

The mobile companies recognise the difficultiesincurred by the Emergency Services when a call ismis-routed. To keep these mis-routes to a mini-mum, they require the emergency authorities toinform the mobile companies when a mis-routehas taken place to enable then to investigate thecircumstances surrounding the call.

The final responsibility for the overall correct rout-ing of 999/112 emergency calls rests with the cel-lular companies.

4.8.1 Name and Address Information ofMobile Callers

The licence agreements of Cellnet and Vodafonerestrict these companies from dealing directly withsubscribers, their services can only be boughtthrough Service Providers.

Although EA's require 24 hour access to sub-scriber records, the records of Cellnet andVodafone customers, who have purchased theirmobile telephone from an independent ServiceProvider, are not always available on a 24 hourbasis. The Service Providers are not obligated bytheir licence to provide 24 hour access to customerinformation. Therefore, it may be difficult to fol-low-up a 999 call which has been interrupted orterminated in suspicious circumstances.

The Federation of Communication Services (a tradeassociation of the mobile communications industry)have informed OFTEL that it is not commerciallyviable for all Service Providers to provide 24 houraccess given the small number of cases involved.

The licence agreements of One2One and Orangeenable them to supply their customers directly.Therefore, most of their subscriber information isavailable on a 24 hour basis. Only a small percent-age of their customers use High Street serviceproviders.

It should be noted that licence agreements are sub-ject to change. However, Brigades will be keptinformed of all 999 issues through the 999 LiaisonCommittee.

Subscriber information for Cable customers is heldby BT and Cable & Wireless.

4.8.2 Release of Subscriber information

The principles and procedures applying to therecording of calls, and the release of subscriberinformation for emergency calls originating in anymobile network, is the same as those applying toemergency calls originating in the fixed network.

All the cellular 999/112 services work in muchthe same way. Therefore, a detailed descriptionof one system may be helpful.


4.8.3 System Description - ORANGE

Orange Personal Communications System (PCS,sometimes referred to as Personal Communi-cations Network (PCN)) use BT's facilities to con-nect 999/112 calls to Emergency AuthoritiesControl Centres (EACCs). All 999/112 calls gen-erated from the Orange digital network will berouted to one of six BT Operator AssistanceCentres from one of thirteen Orange switches,each of which has a minimum of two routes intoBT's network. Routing design within Orangeensures that 999/112 calls are sent to BT at theoriginating switch first, followed by alternativerouting throughout the total network. This guaran-tees delivery of a 999/112 call in all cases, barringa major network disaster within Orange.

The principle behind Personal CommunicationsNetworks (PCNs) is the multiple re-use of valu-able radio channels. The country is divided up intoa series of 'cells', each served by its own low pow-ered transmitter/receiver (base station). Each ofthese base stations is assigned a set of frequenciesdiffering from those assigned to adjacent cells. Theresulting pattern can be repeated enabling radiochannels to be used again but geographically far

Figure 4.5a

Figure 4.5 Ax the caller moves around between cells, the PCN system automatically switches the signal between base

stations without interrupting the call.(Graphic: One 2 One)

enough away to prevent interference.

The very nature of the provision of radio telephonecommunication means that users do not necessari-ly know their exact location and the radio commu-nication system cannot pin-point the caller either.The resultant problem in a cellphone user havingto detail this information when making a 999/112call is likely to lead to delays in satisfactorilyreporting particular incidents. However, in everycase the caller should be asked to state their loca-tion.

4.8.4 Cell/EA Boundaries

Comparison of cell site boundaries and EA bound-aries shows that cell boundaries are unlikely tooverlap more than two adjacent EA coverageareas. Where a cell coverage area straddles two ormore EA coverage areas, a particular EACC willbe agreed and nominated, to which 999/112 callsfrom that cell are to be directed.

4.8.5 Routing 999/112 Calls to EACCs

To enable the Operator to connect a cellphone999/112 call to the correct EACC, a map of the UK

Figure 4.5b


PHONE

ONE 2 ONE

TELEPHONE EXCHANGE

ONE 2 ONEPCN

TELEPHONE EXCHANGE

PCN BASE

STATION

CONNECTIONS TO :

OTHER PCN PHONES

CELLULAR PHONES

INTERNATIONAL CALLS

PCN BASESTATION

LOCALEXCHANGE

LOCAL

EXCHANGE

PCN BASE

STATION

PCN

PCN BASESTATION

PCN CUSTOMER

A CUSTOMER

WITH A FIXED

with EA zone code areas has been created. The EAboundaries generally follow county boundaries.Each cell within the agreed EA boundaries ismapped to a four digit zone code, (Orange zonecodes are prefixed with '3'Cellnet zone codes areprefixed with '2 ' , Vodafone zone codes are pre-fixed with 'O'). Each zone code will be mapped byBT to the four EAs within the boundary area, eachof which will have advised the PTO of primary,secondary, alternative and evacuation EACC con-nect-to numbers.

On receiving a cellphone 999/112 call, the BTOperator's console displays the caller's number(CLI) and a zone code which identifies the origi-nating base station. A list of EACC connect-tonumbers corresponding with the zone code isautomatically displayed for selection by theOperator.

4.8.6 Cell ID Look-Up Failure

Failure to display an EACC connect-to number onreceipt of cell ID/zone code information isextremely unlikely. However, should this occur theMobile Operator will tell the cellphone caller thatthere is a network fault and that some informationchecking will be necessary. Orange will locate theorigin of the call by determining the cell ID, usingits inherent network facilities. Once the cell ID isprovided, the Mobile Operator will refer to a look-up table and forward the call to the correspondingEACC. This call tracing facility can only be car-ried out if the calling cellphone holds the connec-tion. Post event traces are not possible but recordsare kept by Orange which include time of call,duration, originating cellphone number and thecell which received the call. These records are keptand available for cross-checking for approximate-ly three months.

4.8.7 EACC Connect-to Numbers

The EAs should aim to provide at least two weeksnotice of changes to primary, secondary, alterna-tive and evacuation connect-to numbers to therelevant PTO and mobile operator, who will fol-low their mutually agreed update procedure. Thedate and time that the new numbers becomeeffective should also be stated.

4.8.8 Misrouted Calls

Base station radio reception areas cannot besharply defined or matched exactly to EA bound-aries. Therefore, for some base stations, it isinevitable that a small proportion of calls will orig-inate outside the boundaries of the agreed EACC.Also, there are several other reasons why the basestation handling the call may not be the closest tothe incident i.e.:

The caller is moving and delays reporting anincident.

A distant base station across water can some-times provide a stronger radio path than acloser one on land.

If the caller is in the radio shadow of a hill orlarge building, a more distant base stationmay be selected.

Cellular radio signals can travel long dis-tances in certain weather conditions.

The nearest base station is already fully occu-pied.

It is also possible that the cell ID could give anincorrect but apparently valid code to the Operatordue to a faulty console or a fault in transmitting thedisplay information from the switch.

Once connection is established to the EACC, itis the responsibility of the EA operator to estab-lish that the call is relevant to the EA area, or toinstigate means of transfer if it is not.

This can be achieved in a number of differentways:

In most cases the EA will take the details ofthe call and pass the information on to col-leagues in the correct authority.

The EA operator may recall the Operatorback into circuit and request that the call ispassed to another EACC. This may be a dif-ferent emergency service.


The EA operator may advise the Operator ofthe correct EA to handle the call. TheOperator will then look-up the appropriateconnect-to number.

If it is not possible for the EA to advise the correctconnect-to number, or even the correct county,then the Operator will instigate a call trace proce-dure as described, resulting in Orange providingthe location where the cellphone accessed theOrange network. The Operator will then re-routethe cellphone customer to the applicable EA.

The ultimate responsibility for redirecting thecall to the correct EA, however, will rest withthe operating company who will take all rea-sonable steps to do so.

4.9 The satellite telephone

World-wide communications cover is now a com-mon form of communications which is readilyavailable to all, by way of the Inmarsat-Phone,which is capable of transmitting both voice andtext data. It would be true to say, however, that

until recently many brigades felt that such systemswere out of their reach due to the high cost factorin providing the equipment, together with the unitcost of calls. The situation has changed quite dra-matically over the past few years, in that satellitecommunications is now considered an every dayform of transmitting data. The present day equip-ment is both readily available at a reasonable costfor its provision and use.

Such a system of communicating has beenemployed by some UK brigades in the past, mostnotably when a system was obtained on loan andused successfully, by members of UK Fire BrigadeSearch and Rescue Teams whilst in Armenia, fol-lowing the earthquake disaster. Some FireBrigades in Europe regularly use satellite tele-phone systems as an acceptable form of communi-cation and their specialist rescue units carry it aspart of their normal equipment.

The modern range of satellite communicationssystems offers a light and compact package ofequipment which can be set up and ready for usein a matter of minutes. It is also true to say that itis a reliable form of communications which is sim-ple to use from anywhere in the world.

4.10 Public Warning andInformation by Telephone(PWIT)

Nowadays more then 93% of households have atelephone and it is seen as an essential mechanismfor communicating with customers, colleagues,friends and relatives as well as the emergency ser-vices. Telephones are increasingly used to obtain awide range of information, why not use them todisseminate information as well?

There has always been a need to alert the publicabout threats to their safety or provide informationservices at times of major disaster. These disasterscan, for example, take the form of flooding, haz-ardous chemical leaks or even freak weather con-ditions. Traditional warning methods involvingsirens, police with loudhailers or broadcasts fromlocal radio stations have proved not to be particu-larly effective.


Figure 4.6 Satellite telephone.(Photo: Inmarsat)

Early in 1996 the Home Office asked BT TallisConsultancy to investigate how the public tele-phone network might be used to warn and informpeople about impending life threatening incidentsat any time of the day or night.

This investigation also considered the potential ofimproving information services to the public fol-lowing a major incident. Experience has shownthat special telephone numbers broadcast for useby anxious relatives and friends seeking informa-tion about an incident often result in considerabledelays in obtaining the information.

Also in 1996 the Environment Agency awarded acontract to Kingston Communications to develop aflood warning system which would alert peoplevulnerable to flood danger to enable them to takenecessary action to protect themselves and theirproperty. The warning system would also have tonotify the police, emergency services and localauthorities.

The autodial system designed for the EnvironmentAgency by Kingston Communications is capableof sending urgent telephone, facsimile and pagermessages at the rate of approximately 1600 callsan hour using 30 outgoing telephone lines and twofacsimile machines on each line.

Kingston technology is scaleable and a system canbe designed to accommodate any requirement.

Whichever telephone warning system is used itwill almost certainly be backed up with warningsissued through the media.

Following a BT feasibility study, competed in1997, a National Steering Committee has been setup to investigate the possible options of using thenational PSTN network for civil 'disaster' warn-ings. The steering committee includes representa-tives from Central and Local Government, PoliceFire and industry (mainly petro-chemical compa-nies), as well as consultants from the telecommu-nications industry.

A trial of public warning systems by telephone isexpected to go live in Cleveland during 1998. Thisis an area with a large concentration of petro-chem-ical industries, and although the trial could cost

over £1 million this would only be a small propor-tion of the compensation costs of a local disaster.

Public warning by telephone is very new and,unless each recipient pre-registers, gives rise to anumber of the regulatory and data protectionissues. These have now been addressed andOFTEL's view is that unsolicited automated callsmay be used for emergency messages (e.g., wherethere is threat to public safety or their property).

The police, after consultation with industry orother emergency services to asses the risk anddecide what action should be taken, would giveauthority to alert the public via telephone.

4.10.1 How the proposed BT'PWIT'system would work

Select an area. It is expected that the police (asprime users) would use a GeographicalInformation System (GIS) to make use of digitizedOrdnance Survey maps displayed on a PC screen.This enables an operator to zoom into a specificarea and draw a radius or plume, select specificpremises or streets, select zones liable to Hooding,etc. The selection is then translated into OrdnanceSurvey co-ordinates to delineate the required area.

Input the message. The police (with advice froman expert on the hazard) would initiate the emer-gency warning message which may be spoken intothe system, or typed into the computer keyboard.

Send the request. The selected area (in the formof the Ordnance Survey co-ordinates) and the mes-sage are sent electronically over a phone line to theBT distribution centre. Databases are interrogatedto determine the telephone number of all premisesin the selected area (including BT, Cable andWireless, cable TV operators, etc.). A large com-puter system called a Speech Application Platformis used to convert text to speech, where the mes-sage has been input as a text message, call all iden-tified telephone/FAX/pager numbers and monitorthe progress of the calls.

The system could also alert mobile phones whichare active in selected cells, and possibly even sendtext messages to mobiles using the short messageservice (SMS).


Act upon the response. Acknowledgement of themessage is requested by use of the telephone key-pad or by speech recognition. The system will pro-vide a continuous update on acknowledged calls,engaged tone, no answer, answering/fax machines,calls which have been answered but not acknowl-edged, etc.

As an additional feature, the message and a list oftelephone numbers may be sent to the SpeechApplication Platform for delivery by BT. Thisenables numbers which are held on a database (butnot geographically clustered) to be called by BT.

Public Warning by Telephone Systems enablecalls to be made very quickly to any selected areaanywhere in the county and enables positive con-firmation of receipt of the warning. These systemsare more suitable for modern, localised threats andwould not be suitable for alerting millions of peo-ple as would be required under war conditions.



Chapter

5Chapter 5 - Control Centre equipment

KeyBritish AerospaceDopraFortekHoskyns DopraHoskyns HermesMarconiRemsdaqSysecaOther

MobilisingSystems

Figure 5.1 Mobilising Systems used by Brigades — June 1998.

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Highlands&

Islands Grampian

Central

Tayside

Strathclyde

Dumfries &Galloway Northumberland

Lothian&

Borders

Fife

Tyne &Wear

DurhamCleveland

North Yorkshire

Cumbria

Lancashire

Merseyside

WestYorkshire

GreaterManchester South

Yorkshire

DerbyshireCheshireNorth Wales

StaffordshireShropshire

LeicestershireWestMids.

Lincolnshire

Humberside

Hereford &Worcester

Mid &West Wales

South Wales

Somerset

AvonWiltshire Berkshire

Hampshire

Oxfordshire

Gloucestershire

London

Essex

Surrey

West Sussex East Sussex

Kent

Isle of Wight

Cambridgeshire

Suffolk

Norfolk

DorsetDevon

Cornwall

NorthernIreland

Isle of Man

All Fire Services now use computerised mobilis-ing systems to support the call taking and mobilis-ing procedures. These systems comprise severalmain elements:

Integrated Voice Communication Switch.

Computerised Mobilising System.

Communications Interface.

Bearers.

Station End Equipment.

Integrated within the mobilising system are otheroptional features which aid the control staff, forexample, resource displays, mapping systems andautomatic vehicle location systems.

5.1 Control Centre Design

A comprehensive guidance document for FireService Control Centres has been published by theHome Office in DCOL 8/1997, in Scotland asDFM 8/1997 (FRDG Publication 2/97). The docu-ment includes advice on the Control Centre design& ergonomics, procurement and legislation.

The most common workstation configuration for aControl Centre Operator comprises two PC termi-nals, one connected to the mobilising system andthe other to the communications switch. Throughthese two terminals the operator can carry out allmobilising and communications tasks. In somecases a third PC will be used to hold resource dis-play maps and geographical information systems(GIS).

Typically, each operator position in a ControlCentre will be fitted with the same workstationconfiguration and system facilities throughwhich the basic tasks of message handling, log-ging and resource despatching are carried.Occasionally a specially configured supervisoryposition may be installed to provide additionalfacilities such as special monitoring functions oraccess control, etc.

5.2 Communications

5.2.1 Administrative Communications

In centralised mobilising schemes there are con-siderable advantages in segregating administrativecommunications systems from operational sys-tems, though it is common for links to be providedbetween them to give flexibility of usage. Themain advantages of this principle are firstly thatthe operational systems can be much simpler andmore easily duplicated at a number of operatingpositions, and secondly that both operational andadministrative systems can be operated simultane-ously at maximum capacity at any time withoutcausing mutual interference.

In the majority of Control Centres segregationapplies. The administrative PABX telephoneswitchboard is usually in an ideal situation else-where than in a Control Centre and operated bynon-uniformed staff during normal office hours.After office hours, however, when the switchboardis closed, incoming calls are switched on 'nightservice' extensions to terminate on Control Centreequipment.

5.2.2 Safeguards for EmergencyCommunications

The mobilising scheme should have been plannedso that it is not seriously affected by congestion,either in the Control Centre or on its communica-tions systems. It should also be able to functionnormally and without interruption in the event of amains electricity supply failure, either locally atfire stations, or centrally in the main ControlCentre. Either the central control should be safe-guarded so that there is virtually no chance of acomplete breakdown there or, alternatively, thereshould be arrangements made for a secondary con-trol to take over in the event of a serious failure ofthe main control or its communications.

There are, however, technical and economic prob-lems involved in choosing, equipping, staffing andkeeping an alternative control centre in being,solely for the use in the event of a breakdown atthe main control. The general practice has, there-fore, been for the fire authority to invest availablefinancial resources in a highly reliable communi-


cations system and in safeguarding the central con-trol to the maximum possible extent. These safe-guards normally include:

Diversified communications bearers.

Standby power facilities which automaticallycome into operation immediately in the eventof failure of mains electricity supplies.

Adequate fire precaution arrangements e.g.,smoke detectors in communications appara-tus rooms and also in plant rooms and roofspaces which are normally unattended andare a potential risk.

Finally, there should always be predeterminedand practiced last-ditch arrangements, includingthe use of radio and of pre-arranged telephonecontacts. At fire stations there should be an emer-gency un-interrupted power supply (UPS) tomaintain computer and turn out equipment. Itis essential for Control Centres to have an un-interrupted power supply and emergency powergenerator facilities.

5.2.3 Provision of Suitable Circuits

The mobilising 'scheme' should not rely totallyupon access to the public telephone network, sincethis may become congested due either to peak nor-mal usage or to the direct effect of a flood of emer-gency calls to a large incident.

Whilst, in the past, fairly widespread use of thepublic telephone network was made by FireServices for remotely controlling fire station alert-ing systems, this practice was generally speaking,only acceptable when mobilising was decentral-ized on fairly small units such as districts or divi-sions. Nowadays, due to the automation of thetelephone network and the rapid expansion in theamount of telephone traffic, it is no longer regard-ed as satisfactory for emergency call-out purposes.Therefore,the primary bearer could be kilostream,ISDN, radio or a commercially available public-data system such as RAM or Paknet. Whilst thesecondary bearer should be independent of the pri-mary bearer it could be ISDN, radio, data radio, orPSTN.

Some Fire Services also have a tertiary bearer andutilize a commercial paging network to operate thefirefighters callout system. Other Brigades use anoverlay paging scheme on the Brigade mainscheme radio as their tertiary bearer.

So far as the initial connection of 999/112 emer-gency callers is concerned, it is important that ade-quate facilities are provided to enable telephoneoperators to do this very quickly. The introductionof digital exchanges 999/112 services are providedover PSTN lines between Operator Centres and theemergency authorities, these lines being safe-guarded by allowing sole access by the OperatorCentres. As a standby against breakdown of thesecircuits and for use during peak periods, a numberof ex-directory exchange lines are provided in theControl Centre where they appear at all operatorpositions together with the trunk-subscriber circuitterminations.

5.2.4 Alternative Routing of Cables

To minimise the effects of a possible breakdown,the scheme should always include what is knownas 'true alternative routing' of the lines serving thecentral control building, i.e., the provision of atleast two separate cables in different cable ductroutes. This principle should extend, so far as ispractical, to all fire stations particularly whereimportant or 'key' stations are involved. At thecentral control end, essential operational circuitsused for receiving incoming emergency calls andfor remote control call-out facilities should beequally divided between the different duct routesso that, if one of them is interrupted e.g., due toflooding, at least half of the circuits remain inoperation.

5.2.5 Monitoring of Remote Circuits

The circuits which carry remote control facilities,which are the essential backbone of any mobilisingscheme, should always be of the monitored type.These give automatic indication to the ControlCentre operators of faults as and when they devel-op on the network, enabling immediate action tobe taken to get the faults rectified and to imple-ment predetermined alternative arrangements foralerting the affected stations or personnel.


GD92 can be set up to generate traffic whichtests the bearer at regular intervals. The timingof these test signals is set on installation and canbe determined by the brigade.

5.2.6 Exchange Telephone Lines

Exchange telephone lines are commonly used inControl Centres and terminate either on telephoneinstruments, telephone switchboards, line concen-trator units or a digital switch linked to a touchsensitive screen. Some are earmarked for exclu-sive operational use whilst others are for adminis-trative purposes.

The common tendency is for the operational cir-cuits to be terminated on line concentrator units ora digital switch and the administrative circuits tobe terminated on a PABX switch so that calls maybe connected to extensions throughout the organi-zation. A PABX or private branch exchange is asemi automatic switchboard that allows the major-ity of connections via the PABX to be dialleddirect by the extension users, and also may allowexternal callers to directly dial the extension. Thefunction of the switchboard operator is then main-ly confined to answering calls on the main switch-board numbers where the caller is unaware of theextension number or answering queries fromcallers on the internal extensions.

5.2.7 Operational Lines

Where a number of exchange lines serve aControl Centre it is usual for them to be 'ex-directory', under which arrangement the numbersare not disclosed to the public. It is advisable tokeep at least one free for outgoing calls or havethese numbers allocated as incoming calls barredlines. It is not uncommon to apply the facility of'auxiliary working' to such groups of exchangelines, so that when the first numbers or lines ofthe group are in use, the caller is connected auto-matically to one of the free numbers or lines inthat group.

However, one disadvantage of this arrangement,when applied to operational lines in a centralisedmobilising scheme, is that certain fault conditionsin the telephone exchange might put all the lines ofthe group out of action.


It is highly desirable, therefore, to split theemergency and the administrative linesbetween telephone exchanges so that theywould not all be affected by one fault.

5.2.8 Line Concentrator Units andDigital Switches

Line concentrator units allow the operator toaccept a call from whatever source with a singleaction, and are more convenient to use than a num-ber of telephone instruments. These units canaccommodate a variety of types of terminationincluding exchange lines, private wires and tele-phone extensions as well as control terminationsfor the various facilities on Fire Service radioschemes.

These units can easily be repeated, each with iden-tical terminations and facilities at any number ofoperating positions in a Control Centre, to facili-tate the simultaneous handling of a number of dif-ferent calls during busy periods. The terminationof all operational circuits on concentrator unitsavoids the unacceptable bottleneck which wouldbe created if a conventional type of telephoneswitchboard was used.

Where concentrator units are repeated, an incom-ing call is indicated at all positions with a flashinglamp signal. When the call is answered at one posi-tion, the flashing signal on all other positionschanges to a slow wink on the lamp, which indi-cates that the call has been accepted and that thecircuit is engaged until the lamp goes out.

The unit is also suitable for use when monitoringfacilities are required e.g., to enable a supervisor orOfficer-in-Charge to listen in to calls and to breakin and assist when necessary. The same termina-tions and facilities as on the operational positionunits appear also on the supervisory position units,and the circuitry can be so arranged that the actionof 'listening in' does not degrade or in any wayinterfere with the call.

The line concentrator unit is being superseded by adigital switch that incorporates duplication of allkey elements of the switch. Most switches use aPC and 'touch screen' which is linked to the switchvia a high speed local area network or a serial link.

Figure 5.2 Architecture of typical Integrated Communications Control System (ICCS). (Graphic Securicor information Systems)

Many are Integrated Communications ControlSystems (ICCS) which incorporate both telephonyand radio functions.

Different levels of access are available for opera-tors, supervisors and maintenance staff.

Operator access to the system is by means of a touchscreen colour which displays coloured representa-tions of press-buttons. When touched, the systemresponds and begins a series of operations relat-ed directly to the selected button to provide fullcontrol and status displays of all radio and tele-phone functions. Most switches are capable ofqueuing incoming calls and, if necessary, presentthe operator with the oldest call first. This isespecially useful during spate conditions whenemergency calls may be waiting on the system.

The high speed local area network interconnectsoperator positions and the central switch. This net-work broadcasts simultaneous updates to all posi-tions and whilst performing particular functions,the operator is able to call up information from thesystem's database including relevant help mes-sages and telephone directories. In addition, eachoperator position has access to all the facilities

Figure 5.3 A touch screen in use in a Control Centre.(Photo: Simoco)


Engineer Supervisor Operator Operator

Duplicated LAN

DuplicatedServers

ContinuousRecorder

RadioPSTN

PABXPrivate Circuits

Operators Audio

provided by the line concentrator units such as callmonitoring by any other position, intercom andindication of line state and extra facilities such asa system database, recording and playback facili-ties and configuration of both telephone and radiofacilities.

Communications switches either have an integrat-ed call logging facility which can be accessedthrough an RS232 port to an engineering terminal,PC or separate printer, or the ability to connect anindependent call logger. These PC based systemsprovide flexible report generation and the ability tocustomise information presentation of all tele-phone and radio traffic.

Open interface capabilities give the flexibility toconnect external devices including CCTV, lightingsystems, door entry mechanisms and alarm systems.

5.2.9 Automatic Call Distribution

An additional function of call handling equipmentis Automatic Call Distribution (ACD). Incomingemergency and administrative calls are automati-cally presented to available operators on a highestpriority basis. Each call in the queue is presentedto the first operator that releases a line and is avail-able to accept the next incoming call. An electron-ic tone is transmitted to alert the operator that theyhave be allocated a call.

When the call has been completed the operator isallowed a pre-defined amount of time in which tocarry out other essential actions. The system willautomatically present another call when the lapsedtime is reached. Alternatively in cases where anumber of actions are required a manual option to'suspend' the operator from the system is available.

This system is more likely to be used in largerbrigades and has recently been installed inLondon.

5.3 Computerising MobilisingSystem

Clearly the primary Control Centre tasks of inci-dent logging and resource availability are teamactivities which require all operators to haveaccess to the same information.

A variety of mobilising systems are available tobrigades and may be known as either ComputerAided Mobilising Systems, Command and ControlSystems or Mobilising and CommunicationsSystems. All these systems are, as the name sug-gests, systems which incorporate computers to aidthe reception and logging of calls and the despatchof the brigades' resources to incidents.

The incident and resource information recorded onthe mobilising system is of interest to a number ofdepartments outside of the Control Centre e.g., sta-tistics, Press Officer, etc. Much of the informationrequired by control may be prepared or maintainedby other departments and, hence, database updatefacilities must be made available to these depart-ments.

An operator or supervisor's workstation will havea visual display unit (VDU), a keyboard and oftena "mouse' to provide access to the mobilising com-puter. The keyboard may be a standard typewriter(QWERTY) layout or a standard keyboard withsome of the key functions changed to dedicatedfunctions.

5.3.1 Mobilising System Functions

The main function of the mobilising system is toaid the recording of call information and thedespatch of the selected resources. Secondaryfunctions include displaying alarm conditions forthe system and the generation of statistical infor-mation.

Upon entry of an incident type and address into apredefined format the system will interrogate itsdatabase to match the address information. If anexact match is not found the system may offer sim-ilar sounding addresses to the operator. It may alsosearch for risks, duplicate incidents, telephonekiosks, map references, etc., so as to provide theoperator with as much information as is possible.When an address match is made the operator ispresented with a pre-determined attendance andpossibly a recommended attendance.

The operator is then able to accept the offeredattendance, mobilise an alternative or defer theincident, placing it in an incident queue or mergingit as in "same as all calls".


Figure 5.4 TypicalOperator Workstation.(Graphic: Fortek

To undertake these tasks the mobilising systemaccesses various databases that are part of the sys-tem, such as an address gazetteer, pre-determinedattendances, risks, special procedures and CHEM-DATA information. It also records the status ofappliances and officers and will not offer resourcesthat are already committed to other incidents.

It must be stressed that the system only makesrecommendations which can be overridden bythe operator. The mobilising system also main-tains a log for each incident recording all theactions associated with that incident. Other logsare also maintained recording other aspects of thesystem not related to incidents, such as communi-cation failures, operators logging in and out of thesystem, tests, etc.

Once the mobilising system has been used to setup and verify the incident details and proposedresources to attend, the turnout instructions mustbe conveyed to the appropriate fire stations and thecrews alerted. The system will encode the data anddeliver it to the communications network foronward transmission to the appropriate destinationincluding automatic data recovery.

In most instances the communications networkwill comprise of a primary, secondary and possiblya tertiary back-up bearer. The primary bearer willbe the most appropriate bearer for the station tak-

ing into account the number of calls and otherfacilities required, as well as available technology.

Secondary bearers should be independent of theprimary bearer so that any failure will not affectboth bearers. Examples of bearers used areKilostream circuits, ISDN and PSTN telephonelines and radio links including dedicated data net-works and brigade radio schemes.

The station end equipment must be able to receiveand respond to control centre messages for turnoutinstructions from both primary and the secondarybearers.

In 1992 the Home Office produced a specification(known as GD92) for a standard communicationsprotocol to be used for all operational communica-tions between the control centre and the stationend equipment.

The main objectives of the specification were thatproducts could be procured by fire authoritiesunder a Framework Arrangement and would beinteroperable with other products from the same,or different, contractors. In addition, Brigades andcontractors should be able to enhance the basicproducts without affecting interoperability.

The Framework Arrangement was able to meet theneed for provision of equipment with the differing


capacities and performance required by differentbrigades whilst providing the benefit of economiesof scale and boundary independence.

The specification was also beneficial to brigadesprocuring equipment outside the FrameworkAgreement.

GD92 defines a standard protocol and messageformat for mobilising systems over commercial-ly available bearers. This protocol is now usedby the majority of Fire Brigades.

For each of these bearers the protocols and mes-sage formats have been designed to ensure that themobilising system and, hence, the operator, isadvised of the delivery or non delivery of each'turn out' instruction. The protocol supportsadministrative messages, equipment status mes-saging and other functions such as burglar and firealarm activation, power failure and restorationmessages, and tests of mobilising links to ensuretheir availability.

GD92 also supports two way messaging and,hence, station personnel can prepare messageslocally and send them into control, the most com-mon example of this being the entering of staffinglevels at a change of shift.

Station equipment has become increasinglysophisticated and is generally controlled by amicro-processor or computer. The system willcheck the incoming data to ensure that it is validand then undertake a series of localised actionswhich may include:

Control of mains powered equipment such aslights, doors and exhaust extract.

Signalling to crew alarms including audiblealarms, alerters, appliance indicator lights.

Confirmation to the control centre that uncor-rupted data has been received, peripheralequipment has operated and crews haveacknowledged.

In addition to this, they may also run self checkingroutines to ensure that they are functioning cor-rectly, that the bearers are functioning correctly,and that other conditions such as mains power andbattery status are monitored.

Mobilising system architecture generally falls intotwo basic categories:

(1) Central Processing; or(2) Distributed Processing


Figure 5.5 MobilisingSystem Configuration(Graphic: Fortek)

Operator Position

AsFigure One

Main Server

AdditionalOperatorPositions

AsRequired

Bearers to Stations

CommunicationsProcessor One

Main LAN

Backup LAN

Bearers to Stations Bearers to Stations

Bridgeconnecting toother NetworkSystems

Hot StandbyServer NT Server

CommunicationsProcessor Two

The workstations and/or processors are linkedtogether by means of a local area network thusproviding a communications path to the variouselements of the system. Redundancy is provided inthe system so that failure of any particular elementwill not inhibit the mobilising process.

1 Central Processing - Various standard com-puter configurations can be implemented in aclient/server system, consisting of PC work-stations connected via a network to a server.The server requires an operating system thatis not only able to support multiple work sta-tions, but also has the processing capabilitiesof high level programming languages, sys-tems such as 'Unix' or 'Microsoft NT' fulfilthese requirements. In addition, processorsare required to provide the communicationinterface from the mobilising system to thebearers and hence the station ends.

Resilience is provided by incorporatingredundancy within the system. Dual serversare provided, one operating as a 'hot' stand-by, i.e., the secondary server is continuallybeing updated in 'real time' by the masterserver, so that in the event of failure of themaster server the secondary server is able totake over the function of the master server.

The secondary server may be in a differentlocation within the same site, i.e., a differentbuilding within a control complex. This buildsin some additional resilience in the event ofsystem failure to the main control room.

The communications processors are alsoduplicated but as these do not incorporatedynamic databases both are operating togeth-er but are able to mobilise the brigade inde-pendently in the event of failure of one ofthem. As the work stations are in effect'dumb' terminals, failure of one workstationprocessor will not jeopardise the mobilisingsystem but will only render that workstationinoperative. Again, it is possible that the com-munications processors are in different loca-tions within the same site.

2 Distributed Processing - Workstationprocessors are connected by a local area net-

work but in this configuration the work sta-tion processors are high level processorswhich hold all the data base information suchas incident logs and PDAs. One processor isdeemed to be the master processor and co-ordinates the processes of the other work sta-tions. In the event of failure of this masterprocessor, then another workstation can bedesignated as the master. Communicationswith other peripherals is carried out by otherprocessors on the network, for example, eachfire station has a processor on the networkwhich is connected to the bearer interfaces.

It is desirable that local area networks used formobilising should not allow access from other net-works, this could lead to congestion or failure ofthe mobilising system by corruption.

Consideration should be given to protecting themobilising local area network and providingappropriate 'fire walls' where necessary. With cur-rent technology it is possible to provide more thanone network connection on a work station thusproviding an operator with the presentation ofinformation from different networks but not pro-viding any interconnection of the networks.

Information required by other brigade departments,such as incident logs or statistical data, may bedownloaded at pre-determined times or in 'realtime' to another computer system for interrogationand processing. Conversely data may be retrievedfrom other brigade computer systems by the mobil-ising system for use in the processing of incidents.

5.4 Ancillary Control Facilities

5.4.1 Voice Recorders

Fire Services record incoming emergency callsautomatically by using various types of voicerecording machines ranging from the relativelysimple single and multi-track tape machines to PCbased digital recorders with automatic time injec-tion. It is customary to devote an individual trackon a multi-track machine to each workstation andderive the audio from the connections to the oper-ator's headset enabling all land lines and radiochannels in use at that particular work station to berecorded.


Although voice recordings are not used to assistturnout, they are nevertheless sometimes usefulfor verifying the accuracy of an address or otherinformation. They are also used at subsequentenquiries to prove what in fact was said on a par-ticular occasion both by the caller and the FireService operator. Recordings of emergency callsare frequently used as training aids to helptrainees appreciate the problems in extracting ade-quate information from agitated callers. They arealso used to aid identification of callers who havemade malicious fire calls, and there have beeninstances where, when faced with a voice record-ing the culprit has confessed to being the origina-tor of a false alarm.

5.4.2 Availability and Fire SituationDisplay

Every Control Centre must have, in one form oranother, an accurate and up-to-date record of thelocation and availability of appliances, equipmentand officers on standby for immediate turnout.This display is used primarily for ensuring that theresources of a predetermined first attendance are infact available for despatching when an emergencycall is received. It is also used as an aid to theOfficer-in-Charge of the Control Centre when con-sidering 'covering' moves to maintain an equaldistribution of fire cover throughout the area dur-ing periods of intense activity.

Fire situation information throughout the mobilis-ing area at any time must also be displayed, andthis must be kept up to date and in step with themobilising moves. The fire situation display wouldnormally show the address of the incident, theappliances and officers attending, whether or not astop message has been received and very briefinformation likely to be needed by Control Centrestaff or senior officers.

The types of display used for these purposes varya great deal in different brigades. The general prac-tice in the past has been to use a combined gener-al-purpose and appliances-availability wall map,with separate boards marked out for recording firesituation details. In such cases the map will indi-cate every available appliance by means of talliesor coloured lamps. It is common to find separate'officer-availability' boards which indicate where

an officer is and whether available by radio, pageror telephone contact.

When an appliance or officer leaves their station,whether it be to an incident, for drill or other pur-poses, the appropriate tally or lamp is deleted fromthe availability board or map and shown either onthe fire situation display board in the case of anincident, or in an appropriate section of the mobil-ising board where provision is made to recordappliances and/or officers which are not immedi-ately available for operational use.

With the advent of computerised mobilising sys-tems, the display of information from fire situationdisplays, appliance or officer lists, to PDAs andincident logs has become the norm at each operatorposition. The introduction of graphical informationsystems (GIS) has enabled displays similar inappearance to those presented by the traditionallamp system to be reproduced electronically. Theseresource availability displays, for both appliancesand officers, are driven from the changes in statusof the resources held in the mobilising system data-base. These displays can be presented at each oper-ating position on a VDU and also projected on to awall display, either from the front or the rear.

5.4.3 The Gazetteer

To receive and validate details of an emergency, anoperator relies on a comprehensive gazetteer ofstreets and special locations and/or premises. Allmobilising systems will utilise a gazetteer to vali-date the location of an incident, so clearly thespeed and accuracy with which an operator canconfirm the incident location will depend upon thequality and comprehensiveness of the gazetteer.

As a minimum it will hold a list of street names forthe major towns and district, or parish names forrural areas, additionally, special risk locations willbe included. Associated with each entry in thegazetteer is a list of nearest pumps and specialappliances (PDA) from which the operator canselect the most suitable response to the incident.

Increasingly the quality of the gazetteer data isbeing improved and extended to work with digitalmaps. In most brigades an extensive map databaseis held on the mobilising system, this graphical


database providing an alternative method for vali-dating addresses and also a more appropriatemeans for holding risk and general reference data.

5.4.4 Maps

In Control Centres, Ordnance Survey maps of themobilising areas are available for reference pur-poses, giving such information as the boundariesof the area and the location of stations. In addition,larger scale maps may be held, together with plansand diagrams giving details of motorways (withtheir access and exit points), dock and harbourareas, new city development complexes, unusualspecial risks, etc. Street maps, often in a book for-mat, are also held to assist with the location ofstreets and to enable directions to be passed toappliances, officers or other agencies.

As the amount of information available to abrigade and required by the fire fighters grows,almost exponentially, the Control Centre is seenincreasingly as the most suitable repository anddistributor of this data. It is now an essentialrequirement that this information can be easilyretrieved through the mobilising workstation eitherfor review by control, or for dispatching to a firestation or incident ground.

This has led to the introduction of commerciallyavailable computer software to support these func-tions. Much of this information is held in graphi-cal, or geographical form. Graphical InformationSystems (GIS) allow mapping data to be manipu-lated and presented to the Control Centre operator.The maps can also be linked to the mobilising sys-tem so that when a database search matches theaddress criteria, the correct map showing theaddress location is displayed to the operator.

These GIS's are able to interact with other soft-ware such as word processors and graphical pre-sentation technology so that composite packagesof information can be developed. Maps of a FireService's area can be presented with facilities tozoom from small scale to large scale presentations.As these maps are composed as a series of layers itis possible to select the level at which certain fea-tures are displayed, e.g., text can be displayed onlywhen it is possible to read it. Overlays can beadded to give details of hydrants and water mains

Figure 5.6 Graphical Information System Display.(Photo: Bedfordshire and Luton Fire and Rescure Service)

or gas pipe lines or any other features that have asignificance to fire service operations.

Using the facilities of word processing and othersoftware, it is possible to display information fromthe inspection of premises as text, with drawings,photographs, diagrams and even video clips alllinked and accessed from the map presentation. Aswith the resource display, this screen of informa-tion may then be displayed at the operator's VDUor projected on to a wall display and, because thedata is held electronically, may also be transmittedto other computer systems including those onappliances or special vehicles.

Brigades are able to obtain maps from OrdnanceSurvey through Service Level Agreements.

5.4.5 Automatic Fire Alarm (AFA)Terminations

The majority of manual AFA terminations weredisconnected when Control Centres migrated tocomputer aided mobilising systems. However,AFA activity can be properly supported by com-puter technology. Such a system is currently in useby some Fire Services which act as a collector sta-tion to commercial premises.


5.4.6 Secondary Control Facilities

Control mobilising systems incorporate a numberof levels of resilience. Duplicated computer sys-tems and fallback bearers each add their own lev-els of security to the system, as does the ability toalert crews locally from the fire station.

These facilities do not, however, cater for the rarepossibility of having to evacuate the main controlcentre. Systems have been developed which per-mit restoration of basic turn out facilities fromother locations.

Different mobilising systems provide differentsecondary control provisions ranging from aportable laptop computer containing the basicmobilising system and communications interfaceto a duplicate control on the same site as the maincontrol or at a remote location.

Secondary control facilities should be providedwith facilities for the reception of emergency andother incoming and outgoing calls, the despatch ofresources and the operation of the main schemeradio at a location that would not be affected by anydisruption to services provided at the main control.This may necessitate locating the secondary controlwith emergency telephone lines from a differentexchange to those of the main control.

5.4.7 Control Centre Software

With the advent of mobilising equipment based onPCs and the proliferation of computer systems inthe workplace Control Centres now have commer-cially available software packages for their use.These systems may reside on PCs that are alsoused for mobilising or on stand alone machines.

These packages generally include:

Word processors for producing text e.g., aidesmemoires, help files and specific instructionswhich can imported into other systems,including the mobilising system.

Spreadsheets for manipulating data.

Presentation software to produce lectures.

Databases to produce statistical analysis andperformance indicator criteria - required bythe Home Office.

Graphical information systems to producemaps and analyse statistical data in a map-ping format.

• Fire reports (FDR 1 's) - required by the HomeOffice.

5.5 Equipment at Fire Stations

5.5.1 Mobilising Computer

Some Brigades utilise a computer on each stationthat acts as a station controller, this controls mostof the equipment associated with the mobilising ofcrews. There are a number of data links to variousitems of equipment as defined below.

5.5.2 Printers

Printers in fire stations are primarily used forreceiving turnout instructions from controls fol-lowing the operation of the 'turnout' alarm system.They can also be used for the receipt of other non-urgent operational information.

5.5.3 Alerter Base Station

Fire stations with retained crews have a base trans-mitter to activate the alerters, this equipment iscapable of alerting crews with a number of differ-ent signals. A positive acknowledgement is trans-mitted via the data link to the mobilising comput-er, and onward to the brigade control room whenthe equipment is actuated.

5.5.4 Public Address System

Many fire stations and headquarters have publicaddress systems of one kind or another, with loud-speakers sited strategically throughout the build-ing. These broadcast routine and domesticannouncements.

A number of Brigades now use improved types ofremotely controlled public address systems onwhole-time stations for alerting crews and thebroadcasting of turnout instructions as well as rou-


Figure 5.7 StationEquipment.(Graphic: Fortex

tine announcements. A number of different tonescan be sent over the systems that enable crews todistinguish the type of message being broadcast.

Station Bells/Alert Tones

A system of alarm bells/tones, usually referred to as'turnout bells' has, from time immemorial, been partof the normal equipment of fire stations. It is usedprimarily for alerting personnel, the turnout instruc-tions being passed by teleprinter or telephone.

On some stations, a simple system of one or morecircuits of bells is used for alerting personnel in allparts of the premises.

5.5.5 Turnout Lighting

Fire stations, both those continually staffed andretained, usually have automatic facilities forswitching on selected lights to illuminate thoseparts of the station that are used by personnelresponding to calls in the hours of darkness.

These lights are generally controlled via a relaybox which, in turn, is connected to the mobilisingcomputer. Following operation they may be on atime switch and stay on for a fixed period of time,or may be reset manually.

5.5.6 Alternative Power Supply

Mobilising equipment should be provided withalternative power facilities for use when the nor-mal power supply fails. The types of system canvary, but in most cases consist of an uninterruptedpower supply (UPS) That is a bank of batteries thatare continually being charged to supply power inthe event of a failure, These are connected to themobilising computer by a data link and will informthe control room of both the failing of and restora-tion of normal power.

5.5.7 Exhaust Extraction Systems

A number of brigades utilise exhaust extractionsystems to remove exhaust fumes from the appli-ance bay. These are normally actuated by theturnout system and will remain on for a set periodof time. They can also be reset manually.

5.5.8 Control of Traffic Signals

In large towns and cities, provision can sometimesbe made for traffic signals in the vicinity of the firestation to be operated by the mobilising computeror from the watchroom, to stop traffic and give fireappliances a clear exit from the station.


5.5.9 Automatic Appliance Room Door

Electrically operated appliance room doors areprovided on some fire stations. In addition to hav-ing manual controls and built in safeguards, thesewill be linked so that they can operate concurrent-ly with the station alerting systems.

5.5.10 Running Call Facilities

Some fire stations provide facilities (with instruc-tions on how to use them), to enable members ofthe public calling personally at the station to sum-mon the brigade. This type of call is known as a'running call'.

Where there is always someone available in thefire station premises, a switch, usually labelled'Fire', is sometimes provided on the front of thefire station for use by the public. This actuates analarm within the station, which alerts personnel fora turnout and summons a firefighter to the frontdoors to obtain particulars from the caller.

At fire stations where there is not always someoneavailable on the premises, e.g., a day staffed orretained station where all personnel attached to thestation turn out on the fire appliances, there is usu-ally a special telephone at the front of the fire sta-tion for use by 'running callers'.

This telephone, suitably illuminated and labelledwith instructions, may sometimes be an ordinaryexchange line with limited dialling facilities toprevent misuse, on which the caller may dial999/112. It could also be a telephone linked to aprivate wire communications network which,when the handset is lifted, connects the callerinstantly to the appropriate Control Centre.

In all cases instructions should be displayed onhow to use 'running call' facilities and includedirections as to what the caller should do if the sys-tem is out of order or if for any other reason thereis no response. If facilities are not provided noticesshould be displayed informing the caller of thelocation of the nearest public telephone.


5.5.11 Enquiry Bell

It is common practice for continuously-staffed sta-tions to have an enquiry bell circuit installed, witha press-button labelled 'Enquiries' at the mainentrance to the station. Operation of the buttonactuates a bell or buzzer in the station. The enquirybell is normally intended for non-urgent enquiriesonly.

5.5.12 Other Ancillary Equipment

With the introduction of modern systems virtuallyany piece of equipment can be operated on theactuation of the station alerting systems. Suchexamples are the switching off of cookers, kettlesand other electrical equipment.


Chapter 6 - Automatic Fire AlarmTransmission SystemsThe purpose of automatic fire detection equipmentis to give early warning of fire. It is essential thatautomatic fire alarm calls should be transmitted toFire Service Control Centres as quickly and reli-ably as possible.

There are many different types of automatic firedetection devices and systems installed withinbuildings to detect one or more of the characteris-tic phenomena of fire (heat, smoke or flame) andactuate alarm devices or systems.

Arrangements for linking automatic fire detec-tion systems with a brigade Control Centre or acommercial Central Alarm Station.

The main elements are:

A means for transmitting signals from theprotected premises to a remote manned centre(RMC), such as a Brigade Control Centre ora Central Alarm Station; and, where the RMCis a Central Alarm Station: the processing ofsignals at the Central Alarm Station.

A means of communication between theCentral Alarm Station and the BrigadeControl Centre.

No matter how comprehensive and efficient an auto-matic fire detection system may be, its task is notfully completed until it has informed those responsi-ble for taking appropriate action that there is a fire inthe building. Therefore, if the purpose of the systemis to protect property, there will need to be an effi-cient and reliable method of transmitting fire signalsautomatically to a remote manned centre unlessthere is a very reliable means of on-site monitoringe.g., at a permanently manned security gate-house. Ifthe fire detection system is intended to satisfy thefire insurer, this will normally be a requirement.

Such a system will also be required in premiseswhere rapid fire brigade attendance is a pre-requi-site of life safety e.g., hospitals, unless the firealarm system is monitored at all times at a fullymanned location.

Where an automatic transmission system is pro-vided, it should transmit a signal to the RMC assoon as the automatic fire alarm system operates.In exceptional circumstances, a time delay unit(TDU) may be provided to permit an investigationprior to the transmission to the RMC. A TDUshould, however, only be used if there is a falsealarm problem that cannot be addressed by othermeans. A TDU is not acceptable in hospitals and,in other premises, it should only be provided afterconsultation with the brigade and the insurer.

The performance of the alarm transmission linkmay be expressed by the probability of an alarmcall being received at the Brigade Control Centrewithin a specified time. The 'time of transmission'is the period, expressed in seconds, between thestart of the transmission of the alarm signal fromthe premises and the point in time of connection tothe fire brigade control. Ideally, this should notexceed 60 seconds.

6.1 Transmission Methods andReliability Issues

As is always the case, economics is a relevant fac-tor which directly affects system planning and,since highly reliable communication systems costmore than less reliable ones, there are a variety ofsystems in use throughout the country.

Mention has been made of Fire Alarm Systems(FAS) being connected via remote manned centres(RMC) to local authority fire brigade ControlCentres. There are, in a few areas, facilities for


FAS to be connected directly to lire brigadeControl Centres, for instance, Merseyside FireBrigade monitor systems within the Merseysidearea.

Devon Fire and Rescue Service collect signalsfrom data transmitters direct into their commandand control computer. Two simple key operationswill display the PDA to the premises on the opera-tor's screen. Warwickshire Fire and RescueService also monitor FAS within Warwickshire(and some outside the county) via a digital com-municator.

Several small areas of the country,(Cambridgeshire, Norfolk, Suffolk and Fife) arecovered by the 'Alarms By Carrier (ABC)' system.This uses the subscriber's normal exchange lineonto which is superimposed an inaudible signal sothat the line is continuously monitored, by BritishTelecom. Fire signals are routed directly to, andmonitored at, the brigade Control Centre where theABC system interfaces with the mobilising sys-tem, this enables the alarm signals to be displayeddirectly onto the mobilising screens.

Other than in a small number of areas, examples ofwhich are contained in the first paragraph above,and in the four counties served by ABC. there aregenerally no facilities for transmission of fire sig-nals from FAS direct to fire brigade ControlCentres (except by 999 autodiallers, the use ofwhich is now discouraged). Signals are normallyrouted to an alarm company Central Alarm Station.

A British Standard Code of Practice, BS 5979(Code of Practice for Remote Centres for AlarmSystems) gives recommendations for the planning,construction, facilities and operation of CentralAlarm Stations that monitor fire alarm, intruderalarm and/or social alarm systems.

The code recommends that the date and time oforigin of all incoming and outgoing signals, andincoming and outgoing communications areautomatically recorded.

With regard to communications with the firebrigade, BS 5979 recommends that there be twoindependent means of outgoing communicationbetween the Central Alarm Station and the Control

Centre of the fire brigade appropriate to the geo-graphical area from which alarm signals arereceived.

This latter caveat is particularly important. It isunacceptable for a Central Alarm Station toreceive connections from FAS in areas forwhich there was no acceptable means of com-munication between the Central Alarm Stationand the relevant fire brigade. It has been knownfor a Central Alarm Station to dial 999 in the hopethat the local brigade will connect them to theappropriate brigade.

The use of the fire brigade administrative tele-phone number for passing fire calls is also unac-ceptable.

The code recommends that the two means of com-munication with the fire brigade be selected fromthe following:

A dedicated voice transmission path.

A supervised data transmission path.

An ex-directory telephone number for theControl Centre (this should be recognisableat the Control Centre as an emergency callfrom the Central Alarm Station).

The 999 system, provided this will result inthe public telecommunications operator rout-ing the call to the appropriate fire brigade(this is clearly only possible if the CentralAlarm Station and the protected premises arelocated within the same fire brigade area).

A single ex-directory telephone number served bytwo or more lines on a hunting group at the firebrigade Control Centre is regarded as two inde-pendent means of communication.

On receipt of a fire alarm signal at the CentralAlarm Station, action should be taken by an oper-ator at the Central Alarm Station to establish com-munications with the appropriate fire brigadeControl Centre within:

(a) 30 seconds for 80% of fire alarm signalsreceived; and


(b) 60 seconds for 98.5% of fire alarm signalsreceived.

Automatic Fire Detection Systems', as issued inDCOL 6/96 (in Scotland as DFM 8/1996).

These times exclude delays in transmission of thesignal from the protected premises to the CentralAlarm Station, and any delays in answering calls atthe fire brigade Control Centre; they represent aform of Central Alarm Station response time.

The Loss Prevention Certification Board (LPCB)operate an approvals scheme for Central AlarmStations that monitor fire alarm systems. TheCentral Alarm Stations are approved to the LPCBLoss Prevention Standard LPS 1020: Requirementsfor Remote Centres for Fire Alarm Systems.

It is a requirement of LPS 1020 that the CentralAlarm Station must be able to offer an LPCBapproved system for the transmission of fire alarmsignals from the protected premises to the CentralAlarm Station, although the approved CentralAlarm Stations can also offer other methods oftransmission that are not approved. Although theLPCB are responsible for the approval scheme, itis operated jointly by the LPCB and its sisterorganisation NACOSS (The National ApprovalCouncil for Security Systems), and inspection ofCentral Alarm Stations is carried out by NACOSS.

The LPCB publish a list of Central Alarm Stationsthat have been approved under LPS 1020. This listindicates, for each Central Alarm Station, the geo-graphic areas from which the Central Alarm Stationis approved to receive fire alarm signals. This pro-vides confidence to the user that there is third partyverification that the Central Alarm Station com-plies with good practice, that there is an agreementwith the relevant fire brigades and that there is suit-able means for passing fire calls to them.

CACFOA and the British Fire ProtectionSystems Association (BFPSA) have developed aModel Agreement relating to AFD systems con-nected to Brigade Control Centres via commer-cial Central Alarm Stations. The ModelAgreement would be between the Local FireAuthority and the Central Alarm Station.

Brigades should make use of the Home Office/CACFOA/BFPSA document entitled 'AvoidingUnwanted False Alarms Generated by

In general, the requirements of LPS 1020 areincorporated within BS 5979. One of theserequirements is that LPS 1020 approved CentralAlarm Stations must prepare a written reportdescribing the circumstances, and action taken, inall cases where the time between receipt of a sig-nal and transmission of information to the firebrigade exceeds 3 minutes. (This includes anydelay in answering the incoming call at the firebrigade Control Centre.)

There are four distinct means for transmitting firesignals from protected premises to RMCs.

These are:

1 Digital Communicators which automaticallydial the Central Alarm Station using PSTN,and transmit a coded signal to a receiver atthe Central Alarm Station.

2 Private circuits, which provide a permanentmonitored transmission path between the pro-tected premises and the Central AlarmStation.

3 British Telecom 'CARE" system, which issimilar in principle to ABC, in that it uses thesubscriber's normal telephone line to carryalarm signals 'piggy back', but is used toroute signals to a Central Alarm Station ratherthan the fire brigade.

4 'Paknet Radio Access' links a protectedpromises to a Central Alarm Station usingVodafone's public data network. Connectingan alarm panel to a Paknet Radio-Pad pro-vides access to the network, enabling alarmsignals to be sent to the Central AlarmStation.

Prior to the widespread introduction of the digitaltelephone network, research showed that digitalcommunicators, which are probably the simplestand least expensive form of transmission system,were relatively slow and less reliable that methodsinvolving private circuits. The speed and resilienceof the digital telephone network has improved the


speed and should have enhanced the reliability ofthis method, but no recent research has been pub-lished on the subject.

Private circuits may, over relatively short dis-tances, be established on a 'point to point" basis,but over longer distances part of the path betweenprotected premises and the Central Alarm Stationis usually shared by many subscribers. In the lattercase, the many subscribers are connected via thealarm companies' ' Satellites' (data concentrators),from where a large number of signals are multi-plexed via private data circuits. This offers a reli-able, fully monitored signal path at, possibly, thehighest cost.

British Telecom's CARE system is quite economi-cal because it uses an existing telephone line. Costis, therefore, independent of distance between theCentral Alarm Station and the protected premises.This system is now available in most areas of thecountry.

Vodafone Data Network provides periodicallymonitored communications between a protectedpremise and a Central Alarm Station, using PaknetRadio Access. The cost is the same as a monitoredtelephone line and is independent of distancebetween the protected premises and the CentralAlarm Station. With radio coverage approaching95% of the UK population, Vodafone DataNetwork is increasingly being adopted for alarmcommunications.

6.2 Social and Community AlarmsCentres

Community (social) alarms are found in the homesof over one million people, who are described as,'vulnerable' in the UK. Most of those people areelderly and/or disabled but there are many othergroups including some of those discharged earlyfrom hospital. Many of the alarms are located inindividual dwellings and are connected to a 24hour Community Alarm Centre (CAC) via thePSTN telephone.

A call to a CAC can be triggered by pressing thebutton on a portable pendant or on the telephone.Similar alarms located in sheltered housingschemes for older people are often activated by

pulling a cord. During the day most 'Sheltered'alarms are monitored by the resident warden andswitched to a CAC when the warden is off duty.Calls can also be triggered remotely by sensors insmoke or intruder alarms, either in individualhomes or in communal areas.

When an alarm (which may relate to a range of sit-uations where help is required) is actuated, eitherremotely or by a resident, an electronic signal istransmitted to the CAC. Detailed informationabout the caller is automatically displayed on theCAC operator's computer screen.

This information could include vital data on thecaller's personal situation including, for example,medical details. Most of the calls received are notemergencies and are usually requests for reassur-ance or information. In many cases a CAC canrespond to a situation by sending out it's ownmobile warden service or alerting family, friendsor neighbours. However, there will be times whenthe operator needs to contact an emergency ser-vice, including the fire service.

The policy of the national Association of Socialand Community Alarm Providers (ASAP) is that,in an emergency, residents should always ring 999directly as this is the quickest way of contactingthe Fire, Police or Ambulance Services.

There are times, however, when a call will be rout-ed via a community alarm centre because:

many residents in sheltered housing do nothave a telephone and their only means of call-ing for the emergency services is via theircommunity alarm;

some residents are able to summon help, per-haps by activating their pendant, but may notbe capable of talking due to a heart attack,stroke or fall etc. A CAC operator may,knowing the circumstances of the caller,decide to call out an emergency service. Theinformation which the centre possessesmay be vital in ensuring the most effectiveresponse from the emergency services;

some calls are automatically routed to theCAC by a smoke or intruder alarm;


some community alarm users are confusedand cannot easily communicate with anyone,including the BT operator. The CAC operatoris a vital intermediary; and

some residents, perhaps because of dementia,who have called the CAC do not realise thatthe situation requires one of the emergencyservices.

In practice, Community Alarm Centres filterout many calls which might otherwise have ledto an unjustified 999 call.

There are approximately 350 CACs in the UK andthe emergency services will regularly receive callsfrom them. CAC operators are in a unique positionto help emergency service control staff if a call isrouted via a CAC because they:

are trained and experienced in dealing withemergencies;

are trained and used to dealing with vulnera-ble people;

have detailed information about the person inneed of help;

will have detailed information on the addressof the emergency and on emergency access tosheltered housing schemes which can bepassed to crews attending the fire;

can reassure the individual and liaise withthem until the brigade arrives; and

can alert and liaise with other agencies andcarers that might need to be involved.

ASAP and CACFOA have agreed proceduresfor filtering and passing emergency calls fromsheltered housing schemes to the fire service.

Should the caller require the fire service one ofthree procedures will be used:

1 CAC operators will dial 999 for emergencycalls to addresses within their own area.

In addition to the name and telephone numberof the control centre and the address of theincident, the CAC operator may give a refer-ence number of the housing scheme (for crossreference to the PDA) and any access codesor instructions.

2 Some Community Alarm Centres monitorcalls over more than one Fire Service area.These become 'out of area' calls which riskbeing mis-routed. The procedure for thesecalls is that the CAC operator will dial 999,give the name of the community alarm cen-tre, ask for the relevant emergency serviceand instruct the BT operator to disregard theCLI shown.

The BT operator will ask for the CAC client'sfull telephone number which is then typedonto the BT screen to give the connect-tonumbers for the area from which the originalcall was made. The community alarm opera-tor will then talk to the EA operator and passdetails of the call.

This process will add about six seconds to thecall but eliminates the risk of 'mis-routes'.BT operators will monitor for the durationof the call.

3 Community Alarm Centres should be givendetails of appropriate ex-directory numbersfor instant access to the relevant EmergencyService Control Centre free of charge.



Figure 7.1 An example of a screen format using an A.V.L. system. (Graphic: Fortek)

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Chapter 7 - Automatic Vehicle LocationSystemsAutomatic Vehicle Location Systems (AVLS) arenot new, they have been used in the United Statestor some time and by a number of security firms inthis country. More recently Ambulance serviceshave taken advantage of the technology to enhancetheir vehicle availability and running times.

Around this time many Fire Services were replacingtheir mobilising and communication systems andrevamping or moving into new Control Centres.

During the upgrade many of the large and expen-sive resource display boards were replaced withscreen based resource displays incorporating sim-ple mapping or full Graphical InformationSystems (GIS).

As Fire Service personnel became aware of thepotential of GIS. it became obvious that questionsabout AVLS, in relation to the Fire Service, wouldsoon be asked.

HM Fire Service Inspectorate took the initiative,and a consultancy project was set up to 'investi-gate the applications and possible benefits ofAutomatic Vehicle Location (AVL) in the U.K.Fire Service'.

The consultancy contract was awarded to FortekComputers Ltd by the Fire and EmergencyPlanning Directorate as part of a Research andDevelopment programme managed by HM FireService Inspectorate. The contract was awarded inOctober 1994 and ran for two years.

The findings of this consultancy were publishedin DCOL 8/1997 (in Scotland as DFM 8/1997).

7.1 AVLS Technology

An Automatic Vehicle Location System has thecapability to report vehicle positions to a centralcontrol centre either at regular intervals or ondemand, or a combination of both. Several tech-nologies are used world wide although in the U.K.two systems predominate.

Systems based on GPS (Global PositioningSystem) utilise time signals received from a con-stellation of 24 satellites moving through preciselydefined orbits to calculate the position of GPSreceiving equipment located in the vehicle. Timingsignals are transmitted by the satellites on analmost continuous basis and hence the vehicleposition is always known providing sufficientsatellites are in view of the GPS receiver. A mini-mum of three satellites (ideally four to eliminatecertain minor inaccuracies) must be in view of thereceiver for it to calculate its position.

A terrestrial based system, as supplied bySecuricor Datatrak Ltd, uses a series of low fre-quency radio base stations to distribute a matrix ofradio signals from which a Datatrak receiver cancalculate its position using a form of triangulation.

In most places both systems can determine a vehi-cle's position to better than 100m and frequentlybetter than 50m. There are, however, locations (e.g.,built up urban areas) where the accuracy of the posi-tional calculations are compromised by physical orgeographical phenomena (e.g., high rise buildingsobscuring the satellites from the GPS receiver).

Both systems require a data network to deliver thepositional data to the communications centre. TheDatatrak system utilises a national radio networkset up specifically for AVL reporting. GPS basedsystems require a mobile data network to be pro-vided. This requirement can be met either by usinga public data network or a PMR channel with adata capability.

The final component of the AVL system involvesthe processing and presentation of the AVL data tosupport the control room and management task ofa fire brigade. While the computation and deliveryof a vehicle's position can be achieved through theuse of commercially available components, theapplication of this data to benefit a fire brigaderequires a degree of customisation.

Figure 7.2 'Mobile Radio' data terminal. (Photo: Fortek)

Figure 7.3 Securicor Datatrak Ltd data terminal.

6 4 Fire Service Manual

Figure 7.4 GPS Antennamounted in centre ofappliance roof.{Photo: Fortek)

Figure 7.5 Dataterminal installed in cab.

Figure 7.6 Mobile Dataequipment in applianceunder rear seat.(Photo: Fortek)


7.2 Potential Benefits of AVLS tothe Fire Service

Potentially, AVL data can be used to assist in thedeployment and mobilising of brigade resourcesand to improve the quality of data recorded againsteach incident.

Knowing the precise location of each brigaderesource should enable the control room to opti-mise resource deployment and to ensure that themost appropriate (quickest suitable) resources aredespatched to an incident.

Present mobilising policy seeks to achieve thisobjective by using Pre-Determined Attendance's(PDA's) which are compiled on the basis of appli-ances being at home station, and, hence, at aknown location when they are despatched to anincident, which in a typical brigade will be the casefor approximately 80% of incidents.

AVL data, therefore, has the potential to assist inthe mobilising of resources to some 20% of inci-dents by providing accurate positional fixes for themobile appliances. This information can then beused by the mobilising system to compute thenearest/quickest appliances to the incident.

Generally speaking, the resource deployment strat-egy used by brigades necessitates standby movesto key stations to cover station areas when appli-ances from that station area are unavailable.Without AVL, an appliance crew report their posi-tion as within a station ground which in manycases is a rather imprecise location.

Through the use of AVLS, a far more precise loca-tion is available for each resource and, hence, theopportunity exists to deploy resources to moreaccurately reflect the needs of the risk areas andtheir corresponding standards of fire cover.

Until recently the only parameter available fordefining location in the preparation of incident sta-tistics and analysis has been station ground. Thissituation has improved slightly in those brigadeswhere the streets and places gazetteer includes agrid reference which can be filed with the incidentlog and used in subsequent analysis.

AVL fitted appliances booked in attendance wouldalso be reporting their exact position and, hence,the position of the incident. Further information,such as the position of the appliance when itbooked mobile to incident could also be saved forfuture response time analysis.

7.3 AVL System Implementation

AVL systems have been implemented in manycommercial organisations and other emergencyservices within and outside of the U.K. An investi-gation into the performance of a number of thesesystems and the experience gained from the PilotSystem installed in Avon Fire Brigade has high-lighted features which will compromise the effec-tiveness of AVL in the Fire Service, the more sig-nificant of which are discussed below.

Most fire brigades see the main benefit of an AVLsystem as being the ability to identify and despatchthe nearest/quickest appliances to an incident,regardless of whether they are mobile or not.While theoretically this is possible, current AVLsystems have not been designed to meet thisrequirement and it is not easily achieved.

The difficulties in achieving this principal objec-tive arise from the errors in the data that will beused in the calculation of the nearest appliance list.These errors derive from:

Inaccuracies in the incident location.

Inaccuracies in the reported positions of eachmobile appliance.

Inaccuracies in computing, for each appli-ance, the running time from its present posi-tion to the incident location.

As with the existing PDA system the acceptablelevel of inaccuracy will vary according to risk andthe associated standards of fire cover. In areaswhere parish, or area, mobilising is used, thelargest source of error will invariably come fromthe incident location. In urban and high risk areaswhere street and premises locations are held in thegazetteer the inaccuracies in the reported vehiclepositions will be the more significant.


It should, therefore, be left to the brigade to spec-ify the accuracy required from the AVL systemand for the supplier to establish whether such anaccuracy can be achieved, and at what cost.

It is difficult to set an expectation of what can bereasonably achieved. However, as a guide, it isreasonable to expect the computed running timesin the list of nearest appliances to be accurate towithin 90 seconds.

The 'Pilot' System showed that the required func-tionality can be met if AVL positional updates aretransmitted with each resource status update, upona request from the mobilising system or controlcentre operator and, periodically, at a rate depen-dant upon the resource status.

If a public data network is to be used then the inter-val for periodic updates could be several minuteswithout seriously compromising the systemintegrity. However, if updates can be delivered atno cost other than network loading then the inter-val set should be such that it does not impact uponthe other data traffic.

Most mobile data terminals and portable PCs cannow be fitted with a GPS transceiver and mosttransceivers will compute the vehicle position tothe level of accuracy required for fire brigade appli-cations. Certain units will perform better than oth-ers in difficult areas such as urban areas wheresatellites may be hidden from view by high build-ings. Therefore, the performance of the proposedGPS transceiver should be checked in variouskey locations throughout the brigade area.

The same approach is recommended if a terrestrialsolution is being considered.

7.4 Operational Considerations

Present mobilising procedures and PDA's reflectthe principle that, if available, an appliance will bedespatched to an incident in its own stationground. In the 'Pilot' site, where this policyapplies, there were numerous occasions whereother appliances, sometimes at home station andsometimes mobile, were calculated to be nearerthan the appliance in whose station ground theincident had occurred.

Furthermore, in busy periods it is conceivable thatappliances will get drawn across the brigade area,on the basis of being the nearest available appli-ance in a sequence of incidents, into areas withwhich they are not familiar and for which theymay not carry appropriate information.

With current resource deployment and mobilisingpolicies AVL data will be of relevance for approx-imately 20% of emergency calls, i.e., when mobileappliances are considered for mobilising.

Through the use of AVL data, it is possible to moveappliances to standby points other than fire sta-tions while still being able to identify the nearestappliances to respond to new incidents. Such a pol-icy, operated in a limited form in one brigade, hasalready shown savings by reducing the need toturn out retained fire stations

7.5 Implementation Costs

The infrastructure requirements (i.e., the need toprovide a two-way mobile data network) of a GPSbased AVL system are such that it would be whol-ly uneconomic to consider setting up a systemsolely for AVL. For both operational and eco-nomic reasons a brigade should consider theintroduction of (IPS based AVL only as part ofa programme to introduce mobile data.

If mobile data can be justified in its own right, thenthe incremental cost of introducing AVL will berelatively small and should definitely be consid-ered.

If the cost of introducing mobile data cannot bejustified, then the benefits which could be provid-ed by AVL at relatively minor additional cost, maymake the difference in justifying the introductionof the mobile data network.

The terrestrial solution offers a different approach.Since the required infrastructure has already beenput in place by Datatrak, it is viable to introduceAVL with relatively little up-front investment.Such a system should provide two-way datawhich, for mobilising purposes, is consideredessential.


7.6 Conclusions

An AVL system operating as part of a two-waymobile data scheme will provide a brigade with theopportunity to simplify, and improve, its mobilis-ing procedures by providing information whichcan be used in selecting the nearest/quickest appli-ances to an incident.

Clearly, busier brigades with a high proportion ofwholetime crews stand to gain the greater benefitsfrom AVL. However, even these brigades wouldneed to consider changing a number of existingoperational procedures.

There would also be a need to make a significantinvestment in upgrading the data, particularly thegazetteer, used by the mobilising system and pos-sibly to upgrade the mobilising system itself.

Without such a commitment it will not be possi-ble to realise the benefit of improved mobilising.

AVL data will also improve the quality of opera-tional and management information, by accuratelylocating all incidents, and logging resource jour-neys to those incidents.

The technology exists to deliver quality data to firefighters and control staff alike, with AVL databeing just one element. In formulating a strategyfor the introduction of new technology it is inap-propriate to view an AVL system as an indepen-dent item, since it will only be effective if it isintroduced as part of a broader overall scheme toimprove the quality of data brigade wide.

At the time of writing (1998), the incremental costof including AVL technology as part of a mobiledata scheme will be relatively low. However, theinvestment required to create the environment inwhich it can be exploited will be significant.



Chapter 8 - Smart and Swipe Cards

Smart Card and Swipe Card systems have been inuse both in the commercial and industrial arenasfor many years, but have rarely been used for fireservice related purposes. Now however, severalfire brigades are using them in a number of differ-ent applications.

These cards employ a number of tried and testedmethods of data capture and transmission, alongwith associated readers. The reading technology ofthese cards may be magnetic, bar code, proximity,inductive or 'smart chip'. Data collected remotelyis passed via a preferred transfer medium, PSTN.ISDN or radio, etc., to a central point for collationand analysis, and can be integrated by both man-agement information and command and controlsystems. For example:

(a) In one brigade bar coded swipe cards are usedfor access control and resource management forretained personnel. These integrated systems haveadvantages at all management levels and enablecontrol staff to know at any given time, the exactnumber and associated skills of retained personnelon station. Brigade managers can analyse levels ofresponse, availability of crews and performance ofboth individuals and stations.

These systems can be used to replace the use ofpaper methods to record and administer personnelmovements that require payment. Swipe card datapassed to the Headquarters network makes theautomatic payment of fees possible, which is espe-cially useful in relation to retained personnel. Drilland training records can be updated and storedelectronically.

Access control eliminates conventional keys andincreases security at remote unmanned stations.

The system could be provided in a number of dif-

ferent formats such as bar codes, magnetic stripand contact or proximity smart cards, which wouldwork in the following way:

Staff members are issued with I.D. cards thatcan be read by remote station terminals, eachcard having been programmed by the CentralProcessor with a level of entry to selectedsites.

At each site an external device controlsaccess via the entry door lock. Members ofstaff are able, therefore, only to gain entry tosites that have been pre-programmed throughthe Central database to allow their access.

bach site also has an internal data terminalthrough which all persons entering arerequired to swipe their card. The data relatingto entry and exist is transmitted (either in realtime or batched) to the Central Processor Unit(CPU) for analysis. This terminal, in effect,logs personnel as 'in attendance' at that sta-tion, where they will remain until loggingout.

External and internal card readers at a site arelinked and the CPU will be aware of someonegaining access to the site without logging in.

Appliances, officers, stand-by crews andancillary staff that require access to stationsat any time are issued with an 'all stations'entry card. All attendees are required to logout thus giving accurate timing of retainedcrews for payment purposes.

Each terminal is fully configurable from the CPU,which means that after installation and commis-sioning only maintenance visits should be neces-sary by the supplier. If a card is lost or damaged it


can be rendered void removing any risk of accessby the finder.

(b) Another brigade uses 'bar-coding' in a differ-ent way: Each member of the Brigade, includingthe Chief Fire Officer and Control Staff, are issuedwith their own personal tally and bar code. At thechange of each tour of duty, the firefighters inserttheir tallies onto the nominal roll board of theappliance they are crewing. The nominal roll boardof the appliance also has a bar code detailing sta-tion, call sign and appliance type.

In the event of a large incident, the IncidentCommand Unit is mobilised and all appliance andpersonnel tallies are handed in to the Unit. Eachbar code is then 'swiped' by an infra red 'pen' tostore the information on a personal computer (PC)

The bar code contains the following information:

Name, rank, station and watch.

Medical details - blood group, allergies,tetanus injections, etc.

Exposure to toxic substances.

Qualifications - LGV, BA wearer, etc.

Other skills which may include - foreign lan-guages, plumber, electrician, etc.

Officer's car registration number.

At any point during the incident, the PC is able toprovide a printout of all personnel in attendance onthe Fireground. This information could be used inthe event of an evacuation. It could also be used todetermine relief crews and provide information topersonnel in attendance should there be a chemicalincident with potential long term effects.

Fire Service requirements are fairly basic atpresent, but full integration with other, avail-able computer systems could provide an effec-tive management tool.



Chapter 9 - CCTV in the Fire Service

Most Fire Service staff will be familiar with thetype of Closed Circuit Television (CCTV) used formonitoring premises for security purposes, eitherin shops, car parks or used to survey headquarters,remote fire stations or even Control Centres —especially at night!

Some years ago the Fire Service recognised thebenefits of capitalising on the technical develop-ments of video cameras, and their ability to trans-mit images by a variety of means, having thepotential to provide the Service with new tools toimprove the efficiency of rescue and assist with thecommand role at incidents. These objectives, aswell as the secondary, but important, benefits ofimproving debriefs, identifying training needs andinforming the public accurately, led them toexplore ways of using this equipment effectivelyon the fireground.

Because firefighters need to know as much as possi-ble about the emergencies and the dangers they maybe facing, the best substitute for seeing somethingdirectly is to have real time video of the same thing.

Visual information of this kind does not add toinformation overload in the way that manuals,plans and procedural documents do. Irrespectiveof whether the incident involves a collapsed build-ing with casualties, a dog lost in a warren or a hugefire that can only seen from one side, there are ben-efits in providing vision using available technolo-gy which would otherwise be difficult, dangerousor impossible to obtain. The use of video equip-ment allows Fire Service personnel to achieve this.

Information may need to be relayed to a Strategic,Tactical or Functional Command, or the ControlCentre. Without doubt. Officers want good qualityinformation about major incidents for debrief,training, enquiries and public relations. Cameras

can be provided in small robust units, and thetransmission and recording methods availableadapted to meet fire service needs.

A number of brigades have been awarded test anddevelopment licences by the Home Office toassess the operational potential to transmit audioand visual colour pictures within an incidentenvironment.

Microwave spectrum is used because a widebandwidth is required to transmit movingcolour images.

For example, one brigade concentrated on gettingvisual information from confined spaces, such ascollapsed buildings or sewers, and used video toimprove effectiveness of command at major inci-dents.

Another brigade uses two separate systems whichenhance their CCTV applications, one has aMicrowave transmitter/Camera, and the other is aCellsend System. A Bodyworn Microwave trans-mitter/Camera System is also used.

These systems are described below.

The Modular Remote Control RapidDeployment Camera System - MAVIS, is aremote controlled camera sending high qualityvision and sound to a control unit operating eitherin the ICLJ or, being fully portable, from a forwardpoint or any remote location.

The CCTV system consists of tripod mountedcolour cameras, a maglight camera, bodyworncamera and ISG thermal imaging camera as wellas a remote control decoder/microwave transmitterand a control case. The control case is mountedin the ICLJ video rack to receive and process the


Figure 9.1 Detail showing camera mounting position. Figure 9.3 One of the original tripod mounted hardThe transmitter can just be seen under the rim of the wired cameras. These cameras are high definition colourhelmet. The camera sees approximately half the normal but do not have a zoom facility. Both new and not so newfield of normal vision. technology work well together.(Photo : BedfordshireFire and Rescue Service) (Photo:BedfordshireFireandRescurService

signals from the microwave cameras. It can oper-ate independently of the ICU.

The bodyworn high resolution colour camera(about 50cm long and lcm square) is mountedunder the right rim of a helmet A microwave trans-mitter is mounted under the rear rim of the helmet.This transmitter takes its power from a harnessmounted battery pack, the antenna is also mountedon the rear rim protruding upwards.

The harness also has a lapel viewer in the form ofa small LCD screen which allows the wearer tomonitor the video picture being transmitted.

The camera is wired to the transmitter through aconnector to allow connection of the ISG ther-mal/video overlay camera if necessary.

The 'Cellsend' system uses digital technology tosend video images from the ICU to the ControlCentre.

Two modems are installed, one in the ICU and theother in the Control Centre. The modem in the ICU

Figure 9.2 BA wearer equipped with high definitionhelmet mounted colour camera. The combined batterypack and control module {mounted on the waistbelt)permits changeover to thermal images from the TIC. Themicrowave antenna and transmitter are mounted on thehelmet to ensure both protection and height for betterimage transmission. (Photo . Bedfordshire fire and Rescue Service)


Figure 9.4 Video rackinstalled in an IncidentCommand Unit. At thetop are the quad andmaster monitors. Belowthis is the real/lapse timevideo recorder. Belowthis is the Cellsendmodem that permitstransmission of picturesto Brigade Control viaGSM telephone.Below this is the videoprocessor for manipulat-ing up to 8 inputs,freezing images andelectronically enlargingif required. Other facili-ties are also available.The unit below this con-trols the mast mountedcamera. The bottom(lighter) unit is thecontrol case for MAVISand the receiver for themicrowave transmissionsfrom both MAVIS andthe helmet camera whichnormally operates withinthe ICU.

(Photo : Bedfordshire Fire and

Rescue Service)

is linked to a mobile GSM phone, while the otheris linked to an extension of the Meridian telephonesystem. The GSM link can be established fromeither end.

Control Centre Operators can choose the resolutionbest suited to the image. In high resolution theimage is updated a few seconds behind real time, atthe lower resolution the image is updated moreslowly but technology will continue to improvethese times. This update rate is achieved by onlyupdating those parts of the picture that move and

the images can be recorded at both ends, it is alsopossible to incorporate an audio facility. 'Cellsend'does not require a PC to operate the system.

Results from tests in these Brigades indicatedthe technology worthy of further research.

The general public are more aware of the FireService than they were in the past. Unusual inci-dents are of widespread interest, especially whererescue is involved and these pictures are in heavydemand from news media.


The opportunities provided by developments incommunications, computing and video technologyenable the Fire Service to provide a more effective,efficient and safe front line service.



Chapter 1 0 - Radio

Figure 10.1 Appliance radio in use.{Photo: HM Fire Service inspectorate)

The Manual of Firemanship first contained, in1954, a section dealing with Radio. At that time,the majority of fire brigades shared the radioscheme (system) used by the local police force.The situation now is completely different; formany years every fire brigade has had its ownradio scheme with a high percentage of fire appli-ances and other vehicles, equipped with modern'transceivers' (radio sets capable of transmittingand receiving).

In addition to the standard radio sets fitted in vehi-cles which communicate primarily with theBrigade Control Room, there is specialised vehicleradio equipment which can communicate with per-sonal radio sets. These provide on-the-spot fire-ground communications and can have the addedfacility of being able to link personal radio setsinto the main brigade radio scheme.

The primary objective of this book is to provide abasic knowledge of how radio schemes work, theircapabilities and their limitations, sufficient to

enable Fire Service personnel to get the best possi-ble use from what is a highly sophisticated techni-cal resource.

There is a continuous demand for improvementsand expansion to radio schemes; for additionalradio 'channels', which permit appliances at differ-ent incidents to be dealt with independently; andfor new facilities of various kinds. Unfortunately,the unlimited expansion of radio as a medium ofcommunication is not possible. It is a finiteresource with clear limits and, as a result, theextent and purposes for which radio may be usedare strictly controlled.

The Radio Frequency and CommunicationsPlanning Unit (RFCPU) undertakes the setting ofcommunications standards and deals with mediumand long term planning needs to ensure that thebest possible communications are provided, takinginto account the rapidly changing technology towhich radio communications, in particular, areprone. Such work includes next generation sys-tems for Emergency Service use, speech and datasecurity, trunking radio schemes, satellites,replacement alerter system planning/evaluation,mobile data, underground radio and line communi-cation.

10.1 Frequency Spectrumcharacteristics, selectionand allocation

10.1.1 The Frequency Spectrum

Radio signals travel through space as a 'wave'which, for the purpose of this explanation, can belikened to a wave on the surface of water. Everysuch wave consists of alternative crests andtroughs to which the following terms apply:


CYCLE - the portion of the wave between succes-sive crests or troughs, which is repeated over andover again to form the continuous wave.

WAVELENGTH - the distance between succes-sive crests, or successive troughs.

FREQUENCY - the number of cycles of wave-lengths, which appear to pass a given point in aspecified time, usually one second. Wavelength,frequency and velocity are related in a very simpleway:

Velocity = Frequency x Wavelength.

However, this formula does not show the relation-ship very clearly. Normally the velocity is a con-stant for a particular type of wave in given condi-tions so more specifically:

Frequency =

or,

Wavelength =

Velocity (constant)

Wavelength

Velocity (constant)

Frequency

Radio waves are just one form of what is known as'electromagnetic radiation', other forms being'micro-waves', infra-red (heat), visible light, ultra-violet and X-rays.

These all have one very important common charac-teristic which is that they all travel through spacewith the same very high velocity. This is 300 mil-lion metres, or 186,000 miles per second. For allearthly distances this is virtually instantaneously.

The only difference between the various forms ofelectromagnetic radiation is that they each occupydifferent ranges of frequency and, hence, differentranges of wavelengths. Radio waves occupy thelowest range of frequencies (and, hence, thelongest range of wavelengths) followed by infra-red, visible light, ultra-violet, and X-rays. Eventhough they occupy the lowest part of the spec-trum, the frequencies of radio waves are quite highin numerical terms. The lowest usable frequencyfor radio communication is about 10,000 Hertz,corresponding to a wavelength of 30,000 metres.

The highest frequency currently in use for radiocommunication within the fire service is about2,300,000,000 Hertz, corresponding to a wave-length of 0.13 metre (13 cms). The Police usehigher frequency bands up to 50 GHz for veryshort (5 kms) links.

1000 Hertz (Hz) is called 1 kiloHertz (kHz)10,000 Hz = 10 kHz1000 kHz = 1 MegaHertz (MHz)1000 MHz = 1 GigaHertz (GHz)

Thus 2,000,000,000 Hertz is more compactlycalled either 2000 MHz or 2 GHz.

The following are two worked examples using theabove formulae:

If a transmission has a wavelength of 4 metres, what isthe frequency?

If a transmission has a frequency of 450 MHz, whichis a similar frequency to the Fireground channels, whatis the wavelength?

where

VelocityFrequency

Thus

Wavelength =

300,000,000 metres per second450 MHz or 450,000,000 Hz

300,000,000

450,000,000metres = 0.88 metres


Frequency =Velocity (constant)

WavelengthHertz

where

Velocity 300,000,000 metres per secondWavelength 4 metres

Thus

Frequency =300,000,000

4= 75,000,000 Hz or 75 MHz

Wavelength =Velocity (constant)

Frequency

Figure 10.2 The electro-

magnetic spectrum

The result is that the higher the frequency theshorter the wavelength. For radio waves, 'wave-length' is measured in 'metres' and 'frequency' ismeasured in 'Cycles per second' for which a spe-cial name 'Hertz' is used.

Figure 10.2 shows how the various forms of elec-tro-magnetic wave occupy different parts of therange of frequencies which are known as the 'elec-tro-magnetic spectrum'. With the exception of vis-ible light the boundaries of the various forms arenot sharp and there is considerable overlap.

Our interest is with the radio wave portion, extend-ing slightly into the micro-wave portion, and thatis expanded in Figure 10.3 with the correspondingwavelengths added.

Radio waves occupy a wide range of frequencieswith the maximum being several million times larg-er than the minimum. This contrasts with the verynarrow range occupied by visible light in which themaximum is only about twice the minimum.

The result is that, whereas the various colour com-ponents of white light normally all behave in thesame way, the lowest range of radio frequencies,e.g., below 100 kHz, will behave quite differentlyfrom the highest range, e.g., above 1 GHz. Thisleads to the 'radio frequency spectrum' beingdivided into relatively small frequency bands,within each of which all frequencies behave inmuch the same way and are therefore, suited to aparticular purpose. Since every frequency has aunique corresponding wavelength the different fre-quency bands correspond to different 'wave-bands'.

10.1.2 Characteristics of the differentFrequency Bands

Figure 10.3 shows, in very broad terms, how thedifferent frequency bands (wavebands) differ withparticular reference to the way they travel throughspace - their 'propagation characteristics', the sizeof the aerials and the power required.

Figure 10.3 Divisions of the radio spectrum


Type ofRadiation

Frequencies

Radio Waves

MicroWaves

MicrowaveOvens

30 300 3000 KHz

3 30 300 3000 MHz

3 30 300 3000 GHzFrequencies too high to express in

"RADIO" units

InfraRed

UltraViolet

XRays

GammaRays

Frequencies

Band Names

Wavelength(metres)

KHz 30 100 300 1000 3000

LowFrequenciesLong Waves(LW)

MediumFrequenciesMediumWaves (MW)

1000 3000 1000 300

KHz

MHz 1

HighFrequenciesShort Waves(SW)

GHz 1

3 10

Very HighFrequenciesShort Waves(VSW)

30 100

Ultra HighFrequencies(UHF)

3 10 30

300 1000 3000

Super HighFrequencies(SHF)

100 30 10 3 1 0.03 0.1 0.03 0.01

CMS 100 30 10 3 1cm

Consider the size of the aerial. It is commonknowledge that, for receiving, the size of the aeri-al is not very important, indeed the vast majority oftransistor radio receivers operate very well with novisible aerial at all. The aerial is a coil woundround a magnetic rod (ferrite aerial). However, fortransmitters the position is totally different; foreffective transmission an external aerial is essen-tial and its length must be carefully matched to thewavelength being transmitted. For the type of aer-ial fitted on vehicles the correct length is almostprecisely one-quarter of the wavelength; e.g., at 30MHz, wavelength 10 metres, this would be 2.5metres. For higher frequencies it is shorter, but forlower frequencies it is longer.

From that, and Figure 10.3, it can be seen that, cur-rently, only two parts of the radio frequency spec-trum are suitable for land-based, mobile and per-sonal radio schemes: the VHF and UHF parts.Unfortunately these parts are also eminently suit-able for many other uses, notably the entertain-ment side, i.e., broadcast radio and television.

There are also allocations to marine, aeronautical,armed services, public utilities, and other commer-cial user requirements. There is, therefore, only alimited allocation available to the emergency ser-vices, of which the Fire Service is only one.

10.1.3 Frequency Selection and Allocation

From the spectrum characteristics in Figure 10.4 itis clear that the allocation of radio frequencies isnot a matter which can be handled in isolation byany one service, by any one government depart-ment, or even by any one country. Agreement hasto be reached on an international basis as to howthe different parts of the spectrum are to be sharedbetween the different types of service for whichthey are best suited. For broadcasting, civil avia-tion and the mercantile marine, operation in thesame bands of frequencies may be either byregional cover or world-wide.

Block allocations of frequencies, by function, areagreed from time to time at conferences of theInternational Telecommunications Union, of whichpractically all countries are members. These blockallocations by broad function are then divided nation-ally among the various users of each type of service.

Low Frequencies (LF) or Long Waves (LW)30 - 300 kHz 10,000 - 1000 metres

Follow earth's curvature. Not screened by moun-tains etc. Consistent long range both by day andby night. Requires very high transmitter powersand very big aerials. The top end of the band iswidely used for broadcasting.

Medium Frequencies (MF) or Medium Waves (MW)300 - 3000 kHz 1000 - 100 metres

Longer ranges by night than by day. Rapidlyvarying effects at sunrise and sunset. Requireshigh transmitter powers and big aerials. Widelyused for broadcasting, Ship-shore radio, marinenavigational aids, etc.

High Frequencies (HF) or Short Waves (SW)3-30 MHz 100-10 metres

Short range over ground, but reflection fromupper atmosphere gives very long range both byday and by night with very little power.Vulnerable to atmospheric disturbances, sunspots,etc. Frequency changes needed every few hoursto maintain continuous communication. Widelyused for long range communication.

Very High Frequencies (VHF) or Very Short Waves30 - 300 MHz 10-1 metre

Screening and reflection by hills, large buildings,etc., becomes noticeable, gradually approachingvisible light characteristics giving significance toline-of-sight. Generally short range over ground,20 miles (30 km) average, almost wholly depen-dent on upon line-of-sight, i.e., height of aerial.Fairly constant results both by day and by nightbut vulnerable to long-range interference duringabnormal weather conditions. Ideal for two-wayland mobile schemes due to relatively short aeri-als and moderate power requirements.

Ultra High Frequencies (UHF) or Ultra Short Waves300 - 3000 MHz 1 - 0.1 metre

Broadly similar to VHF but closer still to visiblelight characteristics. Screening and reflectionmore noticeable, but less long-range interference.Shorter range over ground, but line-of-sight evenmore significant. Lower part of the band is idealfor two-way, hand-held personal radio schemesdue to very short, but efficient aerials and lowpower requirements.

Figure 10.4 Characteristics of different frequency bands


In the United Kingdom, control of the frequencyspectrum is vested in an inter-departmental com-mittee comprising representatives of allGovernment departments with responsibility forfrequency-using services. These include theRadiocommunications Agency of the Departmentof Trade and Industry, the Home Office and theMinistry of Defence. (See the section onRegulatory Issues.)

10.1.4 Channel Spacing

It is not possible to convey information by usingjust a single frequency. A narrow band of frequen-cies is required which is known as a 'Channel'.Different channel widths are required for differentservices: for example, a television video channelmust be many times wider than a speech channel.Channels are normally known by their centre fre-quencies and the centre frequencies of adjacentchannels must be separated by at least the requiredchannel width in order that there shall be no over-lap which would result in unacceptable interfer-ence.

In fact the centre frequency spacing of adjacentchannels are slightly greater than the 'bandwidths'occupied. Several technical factors, including thedesign, build standard and achievable frequencystability all determine allowable channel spacing.Technical advances have made it practicable toreduce channel spacing progressively from 50 kHzto 25 kHz and, currently, to 12.5 kHz. Reductionof the channel spacing specification to which allusers and, hence, all manufacturers must complyhas the effect of increasing the number of channels

which can be made available within a given fre-quency bandwidth. A 100 kHz allocation will taketwo 50 kHz channels or eight 12.5 kHz channels.This is shown in Figure 10.5.

Nevertheless, there are still not nearly enoughradio channels available to meet the growingdemands from would-be mobile and personal radiousers. Further reductions in channel widths andchannel spacing will inevitably be sought as tech-nology continues to improve. The alternative,using digital technology, is to place multiplespeech channels onto one radio carrier by givingeach one a time slot. The TETRA system whichis proposed for the Public Safety RadioCommunications Project (PSRCP) has four speechchannels in a 25 kHz bandwidth channel, whereasGSM, which is the system used for digital cellularradio, currently has 8 speech channels in a 200kHz bandwidth channel. Advances in technologywill soon increase this to 16 speech channels in a200 kHz bandwidth channel.

10.2 Radio Scheme Engineering

10.2.1 Modulation methods

The technique of super-imposing a speech signalon a radio wave is called 'MODULATION'. Theradio wave then becomes the 'carrier' for thespeech and it is often referred to as the 'carrierwave', or simply, the 'carrier'. Basically the radiowave is a single frequency of constant 'amplitude'which means that all the peaks in the wave havethe same height and all the troughs have the samedepth.

100 kHz Channel

2 x 50 kHz Channels

4 x 25 kHz Channels

8 x 12.5 kHz Channels

Figure 10.5 Channel spacing.


Modulation can be superimposed by varying eitherthe frequency or the amplitude of the basic radiocarrier. Thus, there are two techniques currently inuse in the fire service:

(1) Frequency Modulation (FM)

(2) Amplitude Modulation (AM)

Whichever method of modulation is used, theresult is to produce 'side frequencies' just belowand above the carrier frequency. It is the presenceof these side frequencies which causes the radiosignal to require a small band of frequencies, andthey determine the 'bandwidth' of the signal.

Within the narrow channels used for mobile radio(12.5 kHz) there is little difference between AMand FM in terms of 'user-noticeable' performance.In schemes originally provided by the HomeOffice prior to 1989, the main and mobile trans-mitters use amplitude modulation (AM). Whereasin schemes provided and maintained by commer-cial suppliers they may use both AM and FMdepending upon a brigade's stated need to commu-nicate with any adjacent AM brigades.

Simplex and Duplex

The two terms can be taken as a pair. Within thecontext of emergency services' radio, 'simplex'working is that, while transmitting (sending), it is

not possible to receive, so the person receivingcannot interrupt. Any attempt to do so means nei-ther person hears anything. A vital part of 'sim-plex' operating procedure is the use of the word'over'. The speaker must say the word beforeswitching from 'transmit' to 'receive', and the lis-tener must hear the word before switching from'receive' to 'transmit'.

All equipment normally rests in the 'receive'mode, and operation of a 'press-to-speak' key,sometimes known as a 'pressel switch', switchesthe equipment from 'receive' to 'send'. The key orswitch must be released before transmissions fromother stations can be received.

'Simplex' working makes it impossible to speakand listen simultaneously, but it has the advantagesof encouraging a concise and efficient operatingprocedure and an economy in the use of words,and of discouraging lengthy conversations.Further, the equipment required is simpler thanthat needed for 'duplex' working.

Single-frequency

Single frequency radio equipment is designed totransmit and receive on the same frequency.Clearly such equipment can only operate in the'simplex' mode and, in such equipment, thereceiving portion is always effectively switchedoff when the transmitter is activated.

Figure 10.6 Principles of singlefrequency simplex working.


Transmitter Aerialrelay

Aerialrelay

Transmitter

Receiver Receiver

MAIN CONTROL OUT STATIONS

Single frequency working is not used in main VHFradio schemes between brigade control rooms andmobiles, but single frequency personal radioequipment is commonly used by fire brigades fordirect person-to-person working over short dis-tances both with VHF and UHF. (Figure 10.6)

Home Office supplied VHF vehicle-fitted radiosare capable of operating on the two VHF channelsallocated to manpack working.

Double-frequency or two-frequency

Double or two-frequency equipment is radioequipment which is designed to receive on onefrequency and transmit on another and all firebrigade main radio schemes operate on this prin-ciple (Figure 10.7). The need to occupy two chan-nels of the limited available spectrum is a disad-vantage but that is outweighed by the advantagesit affords.

'Two-frequency' working permits 'duplex' opera-tion but, in practice, all fire brigade mobiles are'two-frequency simplex', mainly because of theadvantages of 'simplex' already given.

The advantages of 'two-frequency' working arethat it permits the control station to operate in the'duplex' mode, which in turn allows a mobile to'break-in' to a control station transmission whenurgent attention is required due to a priority mes-

sage. It also permits the engineering of multi-sta-tion, wide area coverage schemes.

10.2.2 Talk-through

An important difference between 'single frequen-cy' working and 'two-frequency' working is that'single-frequency' provides an 'all-hear-all' sys-tem, whereas 'two-frequency' does not. In 'two-frequency' working, all the mobiles can hear con-trol, and control can hear all the mobiles, but themobiles cannot normally hear each other.

A pip-tone 'busy' signal (short 'beeps' about onesecond apart) is, therefore, transmitted by controlwhenever it is receiving from a mobile. It is animportant aspect of radio scheme discipline that nomobile transmits when the 'pips' are on except inurgent, high priority circumstances.

Although the mobiles in a 'two-frequency' systemcannot normally hear each other, there are occa-sions when it is more convenient for them to com-municate directly rather than requiring the controloperator to relay a message. To make this possible,'two-frequency' systems are provided with a facil-ity known as talk-through. 'Talk-through' isselected by the control operator and, when it isselected, the incoming speech from any mobile is'turned round' and re-transmitted. It is, therefore,received by all other mobiles in exactly the sameway as speech from the control operator.

Figure 10.7 Simplex working - outstations only (double frequency).


The control operator can, of course, still hear all themobile transmissions, and retains full control of thescheme. When 'talk-through' is selected, 'pip-tone'is automatically inhibited, either completely orwhenever speech is received from a mobile, andthere may be an increase in the level of backgroundnoise and some degradation of speech quality,which may be noticed because of the link-upbetween the incoming and outgoing channels.

'Two-frequency' working provides a measure ofsecurity because unauthorised listeners can onlyhear one way, normally the 'outgoing' transmis-sions from control to mobiles. However, in firebrigade communications security is a lower priori-ty than speed and it is usually more important fortwo mobiles to talk to one another. 'Talk-through'provides that speed, and some fire brigades chooseto operate their schemes permanently on 'talk-through'.

10.2.3 Wide Area Coverage

This implies that radio communication is requiredover an area greater than that which can be servedby a single base station, no matter how favourableits location may be. All county fire brigade radioschemes fall into this category with the result thatat least two, and in some cases more, base stationsare required. Hence they are known as 'multi-sta-tion schemes'.

One approach would be for the individual mainstations (hill-top sites) to operate on differentchannels, in other words a number of single stationsystems, and not an integrated scheme. However,mobiles receiving from one main station would notbenefit from the 'fill-in' effects of other main sta-tions as they moved into difficult areas.

The system adopted must appear to be a singlestation system even though two or more stationsare involved. It might be thought easy to set all themain transmitters at all the hill-top sites on exact-ly the same frequency, so that their signals mergeinto one in the mobile receivers but it is, in prac-tice, virtually impossible.

10.2.4 The Spaced Carrier System

The original, classic solution to the problem was to

deliberately off-set the frequencies of the maintransmitters within the allocated channel width.The 25kHz channel spacings used at the time per-mitted at lest three slightly off-set main transmitterfrequencies, which a mobile would receive as asingle integrated signal without any noticeableinteraction.

However, with the compulsion to reduce channelspacing to 12.5 kHz, the spaced carrier system hashad to be abandoned because the narrower channelwidth channel does not permit sufficiently largeoffsets to prevent noticeable interaction.

10.2.5 The 'Quasi-Synchronous' or'Common Frequency' System

Fortunately, technical advances have improved thestability of the frequency generators used forscheme main transmitters to the stage where theycan maintain an almost constant frequency overlong periods of time in spite of changing tempera-tures, etc. The main transmitters at different sitesare not exactly synchronous, but they are almost or'Quasi' synchronous.

For all practical purposes they all have the same,common frequency.

As an example, fire brigade scheme main trans-mitters currently operate at about 70 Mhz. The sta-bility of the 'quasi-synchronous' frequency gener-ators is such that the individual main transmittersin a scheme keep to within less than 0.5 cycle persecond of each other.

In conjunction with the method of modulationused, a scheme can be described as 'quasi-syn-chronous amplitude modulation' or 'quasi-syn-chronous frequency modulation', with the alterna-tive term 'common frequency' in place of 'quasi-synchronous'.

Doppler Effect

An effect which may be apparent in 'quasi-syn-chronous' (common frequency) systems, whichwas never apparent in spaced carrier systems is the'Doppler' effect. This is the effect where there isan apparent change of frequency whenever there isrelative motion between a transmitter and receiver.


If the vehicle is moving towards a fixed transmit-ter the frequency appears to increase slightly, but ifthe vehicle is moving away the frequency appearsto decrease slightly.

'Doppler' effect is of no consequence in a singlestation scheme because the change is so smallcompared with the channel width. Likewise, it wasunnoticeable in spaced carrier systems because thechanges are so small compared with the deliberateoff-sets. However, Doppler effect may well benoticeable in quasi-synchronous (common fre-quency) systems when a mobile is in an area whereit receives more or less equal signal strengths fromtwo hill-top sites and is travelling towards one butaway from the other. One frequency appears toincrease while the other appears to decrease withthe result that the difference super-imposes a 'war-ble' or flutter on the received speech which varieswith vehicle speed.

Every effort is made to engineer schemes, by loca-tion of hill-top sites, by adjustment of transmitterpower, by use of directional transmitter aerials,etc., so as to minimise the effects, but because itscause is a natural phenomenon it can never becompletely avoided.

When a mobile is stationary in a position where itreceives more or less equal signals from two sta-tions, the small difference between the two fre-quencies may be noticeable as a slow 'whoosh-ing'. Normally it is only noticeable when the trans-mitter is on without any speech and it does notimpair speech intelligibility. If it is intrusive, asmall change of position, to take advantage oflocal screening from one station, can be advanta-geous.

10.2.6 Scheme Engineering

A number of carefully sited main stations (hill-topsites) are required to give brigade-wide radio com-munication coverage. Figure 10.8 illustrates theway in which such schemes are engineered. Thereare a number of variations, particularly as far asthe linking arrangements are concerned.

Under 'two-frequency working' there are twomain frequencies:

(1) Outgoing - main station transmit and mobilereceive.

(2) Incoming - mobile transmit and main stationreceive. These main frequencies use aerialsat, or near, the tops of the masts, and the aeri-als are almost always omni-directional tocover the largest possible area.

10.2.7 Links

The links between the control station and the mainradio stations can be by land line but the majorityuse radio links (see Figure 10.8). Each radio linkhas its own dedicated pair of frequencies so thatthere is no mutual interference. Directional aerialsare used - commonly known as 'yagis' - similar,apart from size, to TV or FM sound broadcast aeri-als. These aerials 'look at each other' from oppo-site ends of the link to 'beam' the signals and pro-vide the 'point-to-point' mode.

Although, in general, each link has its own trans-mitter and receiver and its own pair of dedicatedfrequencies, the outgoing links from control areidentical. Channels can be saved and made other-wise available if a single outgoing link transmitteris used and its output is split between two or moreaerials, each pointing at a main station. There isthen only one outgoing link frequency but, theremust always be independent incoming link fre-quencies and link equipment.

At each main station, the link transmitters andreceivers are interfaced with the main transmittersso that, for example, a signal from control is:

(1) Transmitted by the link transmitter at the con-trol station.

(2) Received by the link receivers at all the mainstations.

(3) Re-transmitted by all the main transmitters.(4) Received by the mobile receivers.

A similar sequence, in the opposite direction,occurs when a mobile transmits to control.

In general the above descriptions refer to the use ofVHF High-Band linking. Some brigades alsodeploy onward linking at UHF. However, in recentyears there has been a move towards vacating both


VHF and UHF linking in favour of microwave, orland line links. RFCPU have issued policy state-ments addressing this subject (see section onMicrowave).

10.2.8 Frequencies

It is of interest to add up the number of frequencieswhich are permanently needed in multi-station.

Figure I0.8 Multi-station double frequency area coverage scheme.


Mobile station

Main stationMain station "B"

Brigade H.Q.(main control)

FixedMobilestation

Mobile station

Main station "C"Main outgoing frequency

Main incoming frequency

Radio link frequency

Key

Hand-PortableStation

wide-area coverage radio schemes. In the exampleshown (Figure 10.8), a permanent assignment ofeight frequencies is required with independent out-going links to all stations, and this can only bereduced to six if they all share a common outgoinglink, that is, two main frequencies and either six orfour link frequencies to provide just one opera-tional radio channel.

10.2.9 Equipment

It is normal practice in Fire Service radio schemesto provide two sets of equipment at every station,known as the 'main' and the 'stand-by' equipment.Basically, only one is operational at any one timeand their purpose is to ensure continuity of servicein the event of failure. Change-over from 'Main' to'Stand-by' equipment and vice-versa is normallyunder the control of the control station operator orsupervisor. In addition, every station will haveseveral items of ancillary equipment.

At the main control station of a radio scheme,facilities are provided to enable control room staffto isolate the main stations individually when forone reason or another they are troublesome (e.g.,when a temporary, very high noise level is causedby the effects of static electricity during a severestorm in the vicinity of a site).

Remote control facilities are also provided toenable control room staff to switch main stationequipment from 'Main' to 'Stand-by', suchequipment can be changed either individually,i.e., just one faulty piece of equipment, or collec-tively, i.e., all equipment. In addition to the dupli-cation of equipment, a further safeguard is nor-mally provided against complete link failure, per-haps due to aerial damage. The equipment at allmain stations is arranged so that in the event of alink failure the station changes to 'automatictalk-through'.

This means that any signals received from mobilesby the main receiver are automatically re-transmit-ted to the mobiles by the main transmitter insteadof, or in addition to, being transmitted via the linktransmitter to control. This system provides somemeasure of service, which is better than none, untilthe faulty link can be repaired.

Under the automatic talk-through system themobiles can at least talk to each other but the con-trol is isolated if the link is completely severed.Even if the link still works one way the controlwill either hear what is going on without beingable to participate or will be able to speak out with-out knowing whether anyone is receiving.

Figure 10.9 Voiceinfrastructure.


Fixedmobiles atSecondarylocation

Inter-Bde&

ch 21/22

Main ch's +ch&ch 21/22 &Local Control

To hilltop sites (6)

DuplicatedBase

Stations

Appls.

WCars

OPERATORSICCS

Voice Infrastructure

Figure 10.9 shows a typical voice communicationsystem infrastructure which comprises a numberof Control Officer operating positions, each ofwhich is provided with a headset and microphone,a loudspeaker and means of making a radio chan-nel selection. The operating positions provide theControl Operator interfaces to the IntegratedCommunication Control System (ICCS) which inturn provides access to individual radio channelsand also to telephone circuits.

The Main Fire Service voice channel is broadcaston low band VHF from a number of hill top radiosites, at each of which is located either a single orduplicated Base Station. Each Base Station is con-nected to the control site by means of either amicrowave link network or by a private wire cir-cuit. At the control site the receive and transmitsignals are brought together in a Voting unit. Themain purpose of the voter is to accept all of thereceive signals from the hill top sites and select(vote) the best signal to pass to the ICCS.

A local base station at headquarters is connected tothe ICCS to provide for fallback control of themain VHF channel when it is operating in talk-through mode, by operating on the mobile fre-quencies. This base station may also provide com-munication on fireground channels 21 and 22 inthe locality of Fire HQ. Further levels of fallbackprotection are also provided by means of a deskmounted mobile radio located at Fire HQ or at analternative location.

A local base station at headquarters is also con-nected to the ICCS. This provides for inter-Brigade communications with adjacent countyFire Services.

10.2.10 Fixed Mobiles

A unit can either be fixed or mobile but it cannotbe both. However, in the radio sense, a 'fixedmobile' is a radio transmitter/receiver which hasall the attributes of a mobile radio (it might even bephysically identical) except that it is installed in afixed location, within a building, instead of in avehicle. Such a unit transmits on the 'mobile'transmit frequency and receives on the 'main sta-

tion' transmit frequency. Transmissions from sucha unit are received by control in exactly the sameway as transmissions from true mobiles and, apartfrom an identifying call-sign, are totally indistin-guishable from them. Within the context of amobile radio scheme the expression 'fixed mobile'is, therefore, quite logical and understandable.

If a 'fixed mobile' is installed in, or can be operat-ed from, the control room then, in the event of totallink failure, a control room operator will be able tofully participate in whatever remains of the radioscheme through the 'auto-talk-through' facility. Inthis context, the 'fixed mobile' may alternativelybe described as 'reverse frequency' equipmentbecause its transmit and receive frequencies arethe reverse of those for the normal outgoing andincoming control channels. It can also be used as arealistic way of checking hill-top site performancewithin radio range of control.

Although individual fire brigade systems are total-ly independent, it is very useful, for the controlrooms at least, to have access to the schemes ofneighbouring brigades. This facility is useful whenincidents occur over brigade boundaries or whenassistance is sought at large incidents. Such accessis also provided by a 'fixed mobile', each controlroom having a radio which operates on the mobiletransmit and receive frequencies of the neighbour-ing brigade(s).

The fixed mobile originally supplied by the HomeOffice can also be programmed with the two-man-pack frequencies (Channels 21 and 22) allowing,when radio range permits, direct radio communi-cations in an emergency when main scheme fail-ures occur, between control and vehicles.

10.2.11 Main Control

A radio scheme with a considerable number ofusers all operating on the same channel is almostunworkable unless one station is made responsiblefor its overall control. That station is known as the'Main Control', or simply 'Control'. The 'two-fre-quency' system automatically gives the controlstation the ability to 'dominate' all other radioscheme users. Normally they can only hear controland not each other unless talk through is a perma-nent arrangement.


In the Fire Service the main radio control is invari-ably in the centralised mobilising control room forthe brigade, whilst the radio equipment is locatedin an adjacent room or building known as the 'linkroom'. Outside is a tower or mast on which thedirectional link aerials, each pointing at a distanthill-top site, are fitted, along with simpler aerialsfor any 'fixed mobile' equipment in the controlcomplex.

The control equipment will be duplicated at two ormore operating positions, the number of such posi-tions depending upon the size of the brigade andthe number of separate radio channels it uses.

10.2.12 Transportable Equipment

'Mobile' equipment in 'hand-portable' form caneither be in a briefcase, haversack or 'backpack'. Itoperates on the mobile transmit and receive fre-quencies and contains its own (usually) recharge-able batteries. It permits direct contact with controlwhilst away from a parent vehicle and is an alter-native to the personal radios. Because of the lowertransmitter power, imposed by the limited weightfor the batteries, and the less effective aerial, thistype of equipment is not as good as a vehicle radioparticularly for transmitting back to control.

10.2.13 Power Supply Arrangements

The control and main scheme radio equipment at thecontrol station, and all the radio equipment at hill-topsites, are operated from the normal domestic electric-ity supply of 230 volts, 50 Hz, AC. Fire Service per-sonnel should be aware of the potential danger aris-ing from the presence of such voltages and shouldnever attempt to go inside any equipment.

At all key stations there will usually be a stand-bypower supply in the form of a diesel driven gener-ator with automatic start-up and change-over toensure the scheme is never put out of action by amains supply failure.

'Fixed mobile' equipment may be designed tooperate direct from the AC mains, i.e., genuinelyfixed equipment made to operate on 'mobile' fre-quencies, or it may be a 'mobile radio' made tooperate from a vehicle battery, 12 volts, DC, witha 'mains power unit' made to operate from a vehi-

cle battery, 12 volts, DC, with a 'mains power unit'which converts 240 volts, AC, direct to 12 volts,DC, without the need for a battery.

10.2.14 Microwave

In the section on 'scheme engineering' it wasexplained how as many as eight separate frequen-cy channels are required in a three-station schemeto support just one operational channel for abrigade. Additional stations require at least oneadditional frequency (possibly two) whilst an addi-tional operational channel will require a completeadditional set of frequencies. Only two of the fre-quency channels supporting each operationalchannel are used to actually communicate with themobiles - the main outgoing and incoming fre-quencies shown as 'f.a' and 'f.b' in Figure 10.8.The remainder are 'link' frequencies, shown as L1to L6 in Figure 10.8 and they serve to carry speech,on a point-to-point basis, between the control sta-tion and the hill-top sites.

Until very recently the frequencies used for linkchannels have always been in either the VHF bandor the lower part of the UHF 2 band. An obviousdisadvantage is that frequency channels which areideally suited for mobile communication on abroadcast basis are being used for point-to-pointlinks and, with the intense competition anddemand for additional mobile channels, that'waste' of mobile channels can no longer be toler-ated.

To release currently used VHF and UHF 'link'channels for 'mobile' use, regulations now requirethat all new point-to-point links shall immediatelyoperate in the microwave part of the frequencyspectrum and that all currently used VHF and UHF'link' channels shall be moved to microwave aspart of a 'rolling plan'.

Definition

The term 'microwave' is one which has no preciseand universally accepted definition which fits inwith the generally accepted frequency and wavebands given in Figure 10.3. However, for our pur-poses, 'microwaves' means frequencies above 1000Mhz (1 Ghz), that is wavelengths shorter than 0.3metre (30 cms). 'Microwave' ovens operate at 2.45


Ghz so the frequencies which will be used for emer-gency services links - in the range 1.8 to 2.3 Ghz -can be legitimately described as 'microwaves'although Figure 10.3 clearly shows such frequen-cies to be in the upper part of the UHF band.

As far as the operational user of a radio scheme isconcerned, its linking arrangements - its 'schemeengineering' - should be completely transparent,in other words operationally 'invisible'. The usermay work on the assumption that radio signalspass directly between the vehicle aerial and themast at brigade HQ, although it is better to appre-ciate the limitations of radio communication overthe ground, and the need for linked multi-stationschemes.

Limitations

At microwave frequencies, an unobstructed line-of-sight path between aerials at opposite ends of alink, is essential. This is in contrast to VHF linksfor which a degree of obstruction from hills, trees,or buildings, was acceptable. As a result it is notalways possible to replace a VHF link path with anidentical microwave link path. Some reconfigura-tion, either re-routing between existing stations oradditional stations, may be necessary. In VHFlinked schemes every effort was made to linkevery main station (hill-top site) direct from con-trol in a radial 'cartwheel spoke' configuration.

That was not always possible and in some cases avery remote main station is linked to controlthrough another main station which is then knownas a 'master' station or 'repeater' station. Withincreasing congestion of the VHF band, the use of'master' or 'repeater' stations was becoming pro-gressively unworkable, but the move tomicrowave has removed that particular problem,and microwave links are equally likely to bearranged in a 'daisy-chain' configuration.

Microwave links are wide-band in contrast to VHFlinks which were narrow-band. In this context nar-row-band is 12.5 kHz, just one channel width,whilst wide-band is several hundred kilohertzwhich is many channel widths. This means that itis possible for a single microwave link to carrymany separate speech channels using a techniqueknown as 'Multiplexing'.


Figure 10.10 Micro-wave link in 'daisy-chain'configuration.

10.2.15 Multiplexing

'Multiplexing' on a wide band microwave linkdoes not save on frequency spectrum occupiedbecause the total width of a number of multiplexedchannels in a single wide band channel is greaterthan the sum of the widths of the same number ofchannels in individual narrow bands. The big sav-ing is on equipment - one anologue microwavelink can, for example, carry up to 36 separatespeech channels — and on the number of aerialsrequired on the masts.

The multi-channel capability results in anotherpotential change in linking philosophy. Whereas inthe past all the individual emergency services havehad independent radio systems with perhaps theirequipment in different rooms or even differentbuildings at hill-top sites, microwave linked sys-tems planned on a 'combined user service area'basis to meet all the operational requirements of allsharers. Each system will be designed individuallytaking into consideration:

Topography of coverage area, e.g. a county orcounties.

Disposition of existing, and possibly future,hill-top sites.

Disposition of operational controls, e.g., Fireand Police Headquarters etc.

The number of channels and the routingrequired by each user. Figure 10.10 illustrates apossible linking arrangement with Fire and PoliceHQs in different parts of the county.

10.3 Mobile, Transportable andPersonal Radio Equipment

10.3.1 Conventions

Although the actual use of individual channels isnot subject to regulations there are obvious dan-gers if there is not disciplined use. DCOL 4/88 (inScotland DFM 5/1988) recommends that use ofchannels should be identified.

DCOL 6/1992 Item 12 Appendix 1 (in ScotlandDFM 4/1992) recommends the primary and sec-ondary use for each channel.

Since 1 January 1993, 6 UHF 'at incident' chan-nels and 2 VHF channels have been available, inaddition an inter-agency channel is provided.Other users, such as airport fire brigades andworks fire brigades may be permitted to use onechannel if the local authority Chief FireOfficer/Fire Master considers this could improveoperational efficiency and subject to the approvalof RFCPU.

This, for instance, enables an airport fire officerinstant radio contact with responding local author-ity appliances equipped with UHF facilities.

10.3.2 Mobile Equipment

The World Administrative Radio Conference in1979 directed that all emergency services in theUK still operating in the 88-108 Mhz VHFBroadcast Band must move to alternative bands bythe end of 1989. Conversion of old equipment tooperate in the new bands was not consideredworthwhile and the opportunity was taken to re-equip and standardise.

Current mobile equipment for the Fire Service nor-mally receives in the 70-72 Mhz band and nor-mally transmits in the 80-82 Mhz band.

Figure 10.11 A typical vehicle radio control unit.

{Photo: Simoco)

The standard 'mobile radio' consists of two mainparts:

(1) the transmitter/receiver unit; and

(2) the control unit.

The transmitter/receiver unit is the larger of thetwo and is placed within the vehicle. The smaller,control unit is mounted in a convenient positionfor operation by the driver and/or the front seatpassenger. A multi-core control cable with multi-way plugs or sockets connects the two unitstogether. Connected to the control unit are thehandset and the loudspeaker. Provision is made fortwo loudspeakers so that one can be fitted in thecab and one at the rear of an appliance if required.Connected to the main unit are the aerial and thebattery.

Installation

The installation of radio equipment in all vehicles(motor cars in particular), is controlled by therequirements of Health & Safety and compatibili-ty (non-interference) with other sophisticated vehi-cle electronic systems which are now fitted asstandard equipment.

'Standard fits', in which the precise location ofevery part of the radio equipment is defined,should be agreed by the vehicle manufacturers, the


Fire Service and the service provider. The staffwho actually install the equipment have no author-ity to deviate from the 'standard fits' because, inattempting to meet the wishes of vehicle owners, aphysically or electrically dangerous situation mayresult.

Further guidance on installation of mobileradio equipment in fire appliances is availablefrom RFCPU.

10.3.3 The Aerial

It is a truism that any mobile radio is only as goodas its aerial, hence the design of the aerial, and itslocation on the vehicle, largely determine the over-all performance obtained. The type of VHF aerialcurrently fitted on fire mobiles is known as a'quarter-wave rod', its length being almost exactlyone quarter of the transmitted wavelength.

For a transmitter frequency of 80-82 Mhz, thewavelength is about 3.66 metres, so a quarter wave-length is just under one metre.

Ideally the aerial should be mounted in the centreof a flat electrically conducting (i.e., metal) sur-face, such as the roof of a car or van.

Many modern fire appliances have fibre-glass bod-ies and it is customary for an area of metal foil ormesh to be moulded into the roof of the cab duringmanufacture to which the aerial must be fitted. Ifother roof-mounted equipment, such as ladders,are fitted first, care is needed to avoid encroachingon the critical 'aerial space'. Metal close to the aer-ial will absorb the radio energy resulting in inferi-or performance.

The aerial is connected to the transmitter/receiverunit by a coaxial cable, similar to that used to con-nect a TV aerial to a TV set. The performance ofsuch cable is impaired if it is sharply bent orsquashed even though there may be no visible signof damage.

10.3.4 Channel Selection

The mobile radio (as originally supplied by theHome Office) has the capability of accessing up to255 channels but, at the time of writing, only a

limited number are used. Channels 1 to 20 are'brigade allocated' and each brigade has made itsown selection. The brigade's own channel or chan-nels will normally be on channels 1, 2, 3, etc., asrequired, followed by the channels of neighbour-ing brigades by mutual agreement. Channels areselected using a numerical key pad and the illumi-nated display will show the channel numberentered.

Channel numbers 21 and 22 are allocated forworking both with man-pack VHF radio equip-ment and directly between vehicles fitted withsuitable radio equipment.

10.3.5 Squelch

All mobile radios operating at VHF (and UHF)have an automatic'squelch' or 'mute' which com-pletely switches off the receiver output to the loud-speaker and earpiece when no transmission isbeing received. The 'squelch' is necessary to sup-press the noise which would otherwise be heard inthe absence of a signal. The receiver automatically'opens up' when a signal of sufficient strength toover-ride the noise and give an intelligible outputis received. An incorrect setting of squelch levelsaimed at reducing unwanted noise could mean thatvery weak operational signals will not open up thereceiver.

10.3.6 Transmission Timer

To avoid the risk of the transmitter being perma-nently locked on transmit due to a faulty handsetpressel switch or the handset falling into a positionwhere the switch is jammed on, the transmitter isfitted with an automatic transmission timer. Ajammed-on transmitter would block the completeradio scheme, and, being 'simplex', the receiverwould be inactive so that no signals could bereceived. The transmission timer automaticallyswitches off the transmitter after about 30 secondscontinuous operation. Normal transmissions rarelylast that long but, if necessary, the pressel switch issimply released and pressed again to continuetransmitting. The 30 seconds time-out applies toHome Office supplied mobile radio equipment.However, similar principles, but possibly withactual different time-outs, will normally apply toall transceiver equipment.


10.3.7 Power Supplies

The standard mobile radio is designed to operatefrom the standard 12-volt DC vehicle batterysource. Connection is made between the transmit-ter/receiver unit and the vehicle battery via a heavyduty two-wire cable with a suitable fuse in the'non-chassis' (usually positive) wire, the fusehold-er being as close to the battery terminal as possi-ble. The use of two wires, avoiding 'earth return'through the vehicle chassis, helps with equipment'compatibility' by reducing the risk of mutualinterference with vehicle electronic systems.

No problem arises in standard 12-volt vehicles butmany larger vehicles and fire appliances have 24-volt electrical systems. Radios can be built to workoff 24 volts, but it is not economic to have twostandards so 24-volt vehicles are fitted with 12-volt radios.

There are two ways in which this can be done:

(1) By battery tapping. The 24 volts is normal-ly provided by two 12-volt batteries 'inseries' so the radio can be connected acrossthe 'lower' one (the one with one terminal tochassis). This works reasonably well,although the battery supplying the radio willbe discharged more than the other one andthis can cause battery maintenance problems.The main disadvantage of this method is therisk of a vehicle mechanic, unfamiliar withthe unusual arrangement, re-connecting theradio across the full 24 volts when replacingthe batteries. This method is, of course, notpossible if the 24-volt battery is a single unitwith no access to the intermediate 12-voltpoint.

(2) By using 24-volt to 12-volt converters. Theseunits, which are readily available, are easilyfitted to 24-volt vehicles and are far more sat-isfactory. However, there are cost, installationand maintenance overheads to consider.

10.3.8 Fixed Mobile Version

A fixed mobile version of the standard mobileradio is available, designed to be fitted in a rack orcabinet in a building and powered from the normal

230-volt domestic AC mains supply via a powerunit whose output is 12 volts DC.

The radio can be controlled either 'locally' at therack or cabinet, or 'remotely' by a control unitdesigned to fit in a console or be free-standing ona desktop. Emergency power can be made avail-able either via the building backup generator, fromthe uninterrupted power supply, or a direct 12v DCswitchcable or plugged battery supply.

10.3.9 Special Features

(1) Single frequency working

The standard mobile radio normally works in the"two-frequency simplex' mode communicatingwith 'Control' over the main VHF radio schemevia the hill-top sites and the linking system. Theoutstanding feature of 'two-frequency' working isthat the mobiles can only hear 'Control'; they can-not hear each other unless the control operator hasengaged 'talk-through'. Direct 'mobile-to-mobile'communication is possible with 'talk-through'engaged, but that ties up the whole of the 'main-scheme'. The control operator may wish to moni-tor the messages, but all other mobiles are unnec-essarily involved.

To provide greater flexibility the 'standard' mobileradio will have one or two 'single frequency' chan-nels (usually channels 21/22) and any two or moremobiles switched to one of those channels will beable to communicate directly and totally inde-pendently of the main scheme, within a very lim-ited geographical area. The size of the area will bealmost entirely determined by the intervening ter-rain and is likely to be severely restricted in heav-ily built-up areas.

It is of course necessary to pre-arrange the switch tothe single frequency channel. It is even more impor-tant to switch back to the normal two-frequencychannel because there is no way in which 'Control'can contact a mobile switched to the single frequen-cy channel. Under normal circumstances permis-sion will be requested from 'Control' before amobile switches to Channels 21 and 22. The fixedmobile can also operate on Channels 21 and 22 fordirect emergency communications with mobileswhen no other normal channel is available.


(2) CTCSS

CTCSS stands for 'continuous tone controlled sig-nalling system'. It is an optional feature, alreadyfitted in a small number of brigade hilltopreceivers, mobile radios may be similarly fitted.

In the normal way the squelch or mute of a receiv-er is opened by the reception of a 'carrier' signal ofadequate strength. The audio output of the receiv-er is then fed to the loudspeaker or earpiece toreproduce any speech modulation superimposedon the carrier.

This normal system works reasonably well but ithas two disadvantages:

(1) There is no way in which individual mobiles,or groups of mobiles, can be called indepen-dently so that only those for whom a particu-lar message is intended will hear it; and

(2) There are circumstances in which a radioreceiver can be 'fooled' by natural or man-made radio noise' so that its squelch openswhen no real signal is present resulting in a'noise' output. This particularly affects mainVHF scheme hilltop receivers which controlrooms need to maintain a constant listeningwatch.

CTCSS overcomes those disadvantages by super-imposing a continuous low-pitched tone upon theradio 'carrier' at the transmitter, in addition to thespeech. The continuous tone is used to open thesquelch at the receiver, after which it is 'filteredout' so that it is not heard at the audio output. In theoutgoing direction (hilltop-to-mobile) differenttones can be selected by the control operator anddifferent mobiles, or groups of mobiles, willrespond to different tones. This provides what isknown as 'selective calling' in which only selectedmobiles will receive the transmission.

When CTCSS is fitted to inhibit hilltop radioreceivers, remote technical arrangements must befitted to allow Control to switch off the brigade'sCTCSS. This arrangement is necessary to allownon-CTCSS fitted mobiles to access the brigade'sradio scheme upon such a request from the non-CTCSS fitted brigade Control.

10.3.10 Transportable Equipment

'Transportable' in this context, as distinct from'mobile' or 'personal', means equipment which iscompletely self-contained with its own batteriesand aerial, which can thus be transported fromplace to place and used anywhere, but which isusually set down, rather than operated whilst beingcarried, as is the 'norm' for personal equipment.The distinction is, however, somewhat vague andsome transportable equipment is certainly capableof being used 'on the move' as is illustrated by the'hand-portable' (see Figure 10.2).

The standard equipment has a 99 channel capabil-ity and the first twenty channels are 'brigade allo-cated' in the same way as a standard mobile. It alsohas the same 'single frequency' capability usingChannel 21 or 22. It has all the features and facili-ties of a standard mobile except 'public address'.

The biggest demand on the battery is during 'trans-mit' and a compromise must be made between thetransmitter power and the acceptable size andweight of the battery. Of necessity, the transmitterpower is about half that of a standard mobile but inall other respects the performance is identical.


Figure 10.12 Hand-held radio in use.(Photo: Hertfordshire Fire & Rescue Service)

10.3.11 Personal Equipment

'Personal' equipment is small enough to be carriedin the hand or pocket, or in a suitable lightweightbody-harness. Its small size means miniature con-struction techniques which create problem in thereceiver, but which do create difficulties in thetransmitter. The battery size is severely limited andthose two factors restrict the transmitter power to afraction of what is obtainable from 'transportable'equipment (normally approximately 1 watt in themajority of equipment). This, coupled with therestricted aerial dimensions and efficiency, limitsthe range of the transmitter section. The receiverperformance will be comparable to that of a trans-portable under similar conditions.

Personal equipment can operate in either the VHFor the UHF band, but VHF equipment, other thanin the single frequency mode, would normally beexpected to transmit into the main scheme hill-topsites. VHF equipment is perfectly satisfactory on asingle frequency basis to other personal, trans-portable or mobile units over short ranges, but ingeneral UHF offers better performance for person-al radios. The use of FM offers advantages for per-sonal radios, if only because it permits greatertransmitter power to be obtained from a given sizeof battery, and all UHF personal radios used with-in the fire service operate on FM.

10.3.12 Methods of using PersonalRadios

Personal set communication can be organised in anumber of different ways to meet various opera-tional needs which, in broad terms, break downinto the following categories:

Direct person-to-person communication onan exclusive single frequency channel oververy short distances e.g., between individualsat an incident, or when carrying out dry risertests - or other duties - in high rise buildings.

Similar communication but in which one ofthe units is mounted in a vehicle.

Two-frequency communication between per-sonal sets via a vehicle-mounted or portableVHF repeater.

Two-frequency communication between per-sonal sets and the brigade control room via avehicle-mounted UHF/VHF repeater.

Single Frequency Operation

Figure 10.13 (1) involves personal sets only and,although only two are shown, any number can beused on an 'all-hear-all' basis subject to the limita-

Figure 10.13

(1) Single-frequencypersonal set usage.

(2) Single-frequencypersonal sets withcontrol set.


Figure 10.14 Doublefrequency personal setusage with control seton talk-through.

tions of range imposed by location and environ-ment. With more than two units it may well be thecase that unit 'B' can communicate perfectly withboth unit 'A' and unit C whereas units 'A' and 'Ccannot communicate directly at all.

When switched to a single frequency channel apersonal radio transmits and receives on the sameradio frequency and, when used without the aid ofany control station equipment, has the followinglimitations:

(i) Its effective direct range between individualsis seriously affected by the screening phe-nomena. Therefore, the general range andperformance must be expected to vary con-stantly as the individuals move about.

(ii) It is not possible to forecast accurately whatthe performance will be in any particularbuilding or other environment, and it doesnot follow that because good results areobtained in one building, similar results willnecessarily be achieved in a nearby andsimilar building.

To summarise, performance can be expected tovary from one extreme, where screening is severeand when communication even over very shortdistances is unreliable, to the other extreme wherethere is little or no screening, good communicationover several miles is not uncommon.

Figure 10.13 (2) illustrates the use of a control setusing single-frequency equipment. Provided the

control point equipment is well sited and has anefficient aerial, this arrangement has the advantagethat working range between the control point andindividual personal set users is greatly improved.However, with single-frequency working, effec-tive range between individuals depends upon thembeing within direct range of each other, thisarrangement will not improve person-to-personcommunication. The control set operator could,however, personally relay messages from one per-sonal set user to another where they are not withindirect working range.

It should be noted that when a user is transmitting,they will not be able to hear calls from other users.

Two-Frequency UHF Personal Set Channels

UHF multi-channel personal equipment with threeor more channels has been adopted by most firebrigades for fireground purposes. Four of the sixchannels utilise single-frequency working and twoutilise a two-frequency channel. The two-frequen-cy channels cannot be used for direct person-to-person communications without a suitable controlset. Figure 10.14 illustrates the arrangement whichis adopted when using two-frequency personal setchannels. All outgoing transmissions from the'control' set are on one frequency (f.a.) and allincoming transmission from 'personal set' usersare on another frequency, (f.b.). Therefore, sinceall 'personal set' receivers' two-frequency chan-nels are tuned to frequency (f.a.) they cannot heartransmissions direct from other 'personal set'transmitters, which are tuned to frequency (f.b.).


ControlSet

'Talk-through'

Personal Set

Personal Set

Nevertheless, this arrangement has advantagesover single-frequency working especially whenthere is a need to increase working ranges betweenindividuals. This is achieved by a "talkthrough"facility on the 'control set' for use when it is nec-essary to automatically re-transmit on the outgoingfrequency (f.a.) all incoming signals received from'personal set' transmitters on frequency (f.b.).When the 'talk-through' facility is off, the 'controlset' operator will hear and be able to communicatewith all 'personal set' users within range, but 'per-sonal set' users will not be able to hear each other.

There is no reason why the 'control set' should notbe switched to 'talk-through' on the two-frequencychannel and left unattended when the requirementis for good communication between 'personal set'users. All six channels may be used simultaneouslyat the same incident without mutual interference.

The 'talk-through' facility provides considerablyenhanced range between 'personal sets' above thatobtainable with single-frequency working becauseof the greater performance of the vehicle-mountedor 'portable set' and its aerials.

It is customary to designate the direction from con-trol as 'outgoing' and the direction to control as'incoming'. The equipment thus has a true controlfunction, exactly the same as that which thebrigade control room has over the main VHFscheme, hence the operator at the fire ground cancontrol the miniature UHF scheme in just the sameway. Vehicle-mounted sets are normally fullyduplex, usually with separate transmit and receiveaerials although it is possible to use a single aerialwith an additional unit, known as a 'duplexer'which enables the transmitter and receiver to oper-ate independently and simultaneously with a singleaerial.

The conditions of licence, under which frequen-cies are allocated and radio communicationsauthorised, restrict the use of Fire Service person-al sets to low power, short range communications.In consequence, the setting up of fixed base sta-tions on 'personal set' frequencies, VHF or UHF,to give greater working ranges (for example,throughout a town or city) is not permitted becauseof the risk of causing interference to other brigadesin neighbouring areas.

Normally there is no operational requirement forpermanently engineered Fire Service 'personal set'schemes similar to those which are an operationalnecessity for the police. The normal Fire Servicerequirement is the need for completely portable shortrange systems which can be set up and brought intouse at very short notice anywhere at incidents.

At specific locations fixed UHF base stations(repeaters) may be authorised by RFCPU for usein road tunnels or airports, etc. However such useis strictly limited according to the stated opera-tional requirement when the licence was granted.

10.3.13 Composite Units

A vehicle with a mobile UHF control unit willusually have a VHF mobile radio fitted, and anoperator in the vehicle can then communicatewith both the 'personal set' users and thebrigade control room. An added facility is aninterface, usually in the form of a combinedUHF/VHF control unit which connects to bothtransmitter/receiver units.

The equipment collectively is now known as a'VHF/UHF Repeater Unit", and it can be used inthree distinct ways:

(1) Local control of a two-frequency UHF net-work and VHF communication with brigadeHQ, but not simultaneously because althoughthe repeater control unit has two loud-speak-ers, it has only one handset which is switchedto VHF or UHF as required.

(2) Talk-through between 'personal set' userswith the vehicle set unattended or, with thevehicle operator solely involved with VHFcommunication to the Brigade HQ.

(3) With the vehicle control unit switched to'repeat', all signals received on VHF are re-transmitted on UHF and vice versa so that the•personal sets' all hear brigade HQ just like amobile or transportable, and individual per-sonal set users can speak directly back toBrigade HQ.

In (3) above the vehicle will usually be unattendedor at least without a designated operator, and it can


be arranged that when on 'repeat' the two loud-speakers are switched off to prevent unauthorisedlistening-in'. One minor drawback of the repeateris that personal sets are not able to directly com-municate with each other; the vehicle VHF radio is'simplex' and its receiver switches off when trans-mitting. When a personal radio transmits, the UHFreceiver in the vehicle switches on the VHF trans-mitter back to control, and the VHF receiver isswitched off. The UHF transmitter to the personalsets therefore also switches off and they appear togo 'dead'.

10.3.14 Personal Hand-Held Radio Sets

A limited number of frequencies are speciallyallocated on a national basis for use by firebrigades, some in the VHF band and others in theUHF band. Fireground communication ispresently carried out using the UHF band of fre-quencies. Personal hand-held equipment is nor-mally designed to accommodate a minimum of 3channels. However, with the allocation of 6 UK-wide Fire Service UHF frequencies for theirexclusive use and possible additional channelsfor other purposes, there is a need for synthesisedmulti-channel equipment which, for a number ofyears, will be used in addition to existing 3-chan-nel equipment.

10.3.15 Intrinsically Safe PersonalRadios

Ordinary personal radio equipment is capable, inflammable atmospheres, of causing explosions orfire. Intrinsically safe equipment is designed,when correctly used and maintained, to operatesafely even if it develops a fault. Personal radioscertified to BS 5501 Part 7 or European StandardEN50 020 for Category ib. Group IIC andTemperature Class T4, provide the minimum stan-dard that should be used. The harmonised stan-dard CENELEC Eex ib IIC T4, is often referred toand equally valid. (See DCOL 8/95 Item A, inScotland DFM 6/1995 item A.)

Each user should satisfy themselves that thisequipment is suitable for use at incidents in theirarea. If in any doubt about the suitability or useof their equipment then H.M. Fire ServiceInspectorate should be consulted.

10.3.16 B.A. Radio CommunicationsInterfaces

Fire Service Circular 3/75 recommended that allfuture purchases of B.A. should comply with BS4667 and should be covered by a Certificate ofAssurance (C. of A.) issued in accordance with theJoint Testing memorandum.

From 1 January 1990, under COSHH Regulations,BA equipment has to be suitable for its intendeduse and approved by the HSE. It will be certificat-ed under HSE Testing Memorandum No. 3 (TM3).New CEN standards will apply when they becomeavailable.

Any fitting must have the prior approval of themanufacturer who, as the holder of the C.of A., canensure that, if any amendment to the C. of A. isrequired, it will be HSE approved.

10.3.17 Disadvantages of use of radiowith B.A.

Firefighters should particularly bear in mind thatthere are disadvantages to the use of radios with BA.

Radio signal penetration in some types ofbuildings can be limited.

Some atmospheres are so potentially haz-ardous that only communications equipmentwith the highest standard of explosion protec-tion should be used.

Radio systems can operate explosive devicesdesigned to be operated remotely.

Radio transmitters may interfere with build-ing control systems.

10.3.18 User Discipline

The increased use of BA fireground radio general-ly, requires good radio discipline. A very compli-cated radio call-sign system could interfere withoperational flexibility and command at an incidentand, therefore, self-evident call-signs are recom-mended. Call-signs, however, should be such thatthe brigade can be identified from them, especial-ly in a multi-brigade incident.


The possibility of cross-incident and inter-brigadeinterference from the use of over-powerful trans-mitters should be guarded against.

The transmit/receive ratio of the use of radioshould always be considered. Transmissionsshould, wherever possible, be of short durationwith an adequate pause to allow other users of thefrequency, with perhaps a higher priority message,to transmit.

It is not possible for two UHF repeaters or mobilebase stations on the same channel to operate simul-taneously within range of each other. Therefore, itis essential that, where this happens, therepeater/base station in the least advantageouslocation is switched off.

Regulatory approval must be obtained fromRFCPU before specifying the installation of fixedUHF equipment which will be left permanentlyswitched on.

Radio communications could be required to oper-ate deep within an underground railway system,railway tunnels, building sub-basements and othercomplex constructions. The potential of deploy-ing 'throw-out' and 'inbuilt' leaky-feeder sys-tems should be considered even during theearly stages of an incident.

A great deal of research is currently underway toimprove underground radio communications.

10.3.19 Security

Modern hand-held radio equipment is of signifi-cant financial value and can also be of great valueto others, outside the service, if used unlawfully.Accordingly, radio equipment should never be leftunattended on appliances unless it is suitablysecured against theft.

Handheld or portable radios should never be leftexposed to public view in unattended cars, even ifthe car is secured.

Arrangements for securing handheld radios onappliances will vary between brigades. Suitablearrangements could, for example, include a lockedcontainer secured in the appliance from which theradio can be taken when required.

10.3.20 Care Of Hand-Held RadioEquipment

The initial purchase of any handheld radio equip-ment should include suitable protective carryingcases. The design chosen must take account oflocal requirements. Even if the equipment pro-cured is water-resistant the protective case shouldbe designed so that it minimises the chances of thebattery terminals/connections, aerials or controlscoming into contact with water or spray. This isparticularly important where the design of theradio equipment is such that water can collect nearany of these fittings.

Figure 10.15 Trunkingconcept.


Virtually any electrical or electronic equipmentwill fail if subjected continually to heat in excessof that in which it was designed to operate.

Battery compartments of radio equipment shouldbe kept closed (and locked in the case of intrinsi-cally safe equipment) except when batteries arebeing changed. Batteries of explosion protectedequipment must never be changed within the haz-ard area.

Radio equipment should be carried in such a waythat it cannot easily be dropped, strike anothersolid object, become exposed to water, waterspray, corrosive chemicals, or be subject to anyunnecessary or abnormal mechanical stress.

Radios should not be carried in containers withother metallic objects which could make accidentalconnection with battery charging or other externalradio connections. When external equipment notconnected to any socket, a protective cover shouldalways be in place over the exposed connectors.

10.4 Trunked mobile radio systems

The growth in mobile radio systems over the years,and the subsequent demand for frequencies hasplaced an ever increasing load on the spectrummanagers. The concept of 'Trunked' radio schemesgoes far in addressing this problem.

'Trunking' makes greater use of the availablechannels, but leaves users less aware of the con-gestion on that channel. Users share a pool ofchannels and are only allocated a channel whenthey need to make a call. In practice not all userswish to make a call at the same time, and 'trunk-ing' theory is based on the probability that therewill be free channel when required.

The telephone networks have been using 'trunking'theory for a great many years, but it has only recent-ly become economically possible in radio systemswith the advent of microprocessor circuitry.

Fundamentally, 'trunked' radio systems are engi-neered in a similar way to cellular telephony sys-tems, with coverage being modelled in polygonshaped cells, although it is of course possible thatarea coverage is satisfied by a single trunked

basestation. A mobile radio will be constantly"speaking" to its local basestation via a controlchannel.

When the mobile wishes to send a message thecontrol channel will allocate a speech channeldynamically, and communications will be avail-able. At the end of the transmission, and at eachsubsequent transmission different channels may beused. Once the transaction is complete these chan-nels would then be available for other users.

Unlike cellular systems which are generallydesigned to be a one to one service, 'trunked'radio schemes can set up user groups in whichmultiple users will be able to talk.

'Trunked' radios permit 'roaming' throughout thearea required, with handover between radio cellsas a mobile passes from one base station area toanother. The mobile receiver will be constantlyhunting for a control channel during this exercise.Once a signalling channel is identified the sig-nalling information is examined and checked bythe mobile, and if validated, locks the mobile tothis channel. This process happens automatically,and transparently to the user.

In the UK, the MPT 1327 signalling standard isused to facilitate analogue 'trunked' private mobileradio services in "Band III" (174-225MHz)although there is no reason why 'trunked' systemscould not operate in different frequency bands.

Future development in trunked systems is current-ly being addressed by ETSI under the remit of theTrans European Trunked RAdio project (TETRA)which will be a digital TDMA product, with aneffective bandwidth per voice channel of6.25KHz, giving four time slots possible withinthe 25KHz bandwidth.

TETRA will operate for the Emergency Servicesin the band 380-400MHz, and commercially byPAMR service providers in 410-430MHz.



Chapter 11 - Radio Alerting System

Currently Brigades use alerting systems to theHome Office MG4 specification. This forms thefinal link in the overall mobilising system. Thesimple schematic below indicates the system ele-ments involved.

Mobilising and Communications components ofthe overall system are dealt with in detail else-where in this publication. But in the interest ofunderstanding the Alerter system itself a brief out-line may be of help.

The Mobilising system contains a large amount ofdetail covering the whole of the Brigade and this isavailable to Fire Control Officers when assessingthe operational needs of any particular incident.Having determined a station or stations to beturned out, the detail concerning the incident loca-tion, the appliances to attend and, if Wholetime,the operation of sounders or, if Retained, the oper-ation of alerters, is passed to the CommunicationsProcessor.

The Communications Processor makes use of afurther Home Office Protocol called GD92 whichspecifies the way the processor works and the

facilities it must provide. It will normally have anumber of communication links, known as 'bear-ers', between Control and the stations and will usethese on the basis of laid down preference andavailability. The types of 'bearer' available to suchsystems can change as technology makes themavailable and cost effective.

The station end GD92 is similar but on a smallerscale and serves to interpret incoming instructionsand operate printers, sounders, lights, doors, appli-ance bay indicators, etc. In the case of stationswith a retained element instructions from theGD92 unit are passed to the Alerter using theMG4 protocol.

11.1 Alerter - General Description

The requirements of an Alerter system have notchanged in essence since radio alerting was intro-duced. The fundamental need is still to call aretained crew to a station in the case of an incidentor to send a test call to the alerters. What haschanged is the means and the method of operationresulting in greater detail concerning a callsprogress being available at Control.

Figure 11.1 Radio alert-ing system to the Home

Office MG4 specifica-

tion. {Graphic: Muliitime)


It is not always the case that an MG4 alerter isinstalled at the same time as the Communicationssystem is upgraded to GD92. In general, olderMobs/Comms systems presented simple relay con-tact closures to the Alerter and expected a simplerelay contact closure in return to indicate a suc-cessful or failed call. MG4 systems have to be ableto operate in this mode leaving the more advancedMG4 signalling protocol to be implemented at alater date. This gives a Brigade the flexibility toupgrade the overall system on a staged basis.

There are basically two component parts to thesystem, an encoder and a transmitter. The encodergenerates the call required and the transmittersends it to the alerters. It was common practicewith the previous alerter bays to use two transmit-ters in a main and standby configuration. This hasall but disappeared with the new MG4 alerter sys-tems on the grounds that modern transmitters arefar more reliable, but the facility is still availablegiving Brigades the opportunity to take financialadvantage of the improved technology and still usedual bay at certain locations if operational needsdictate.

Standby power is required to cover for the eventu-ality of mains supply failure and normally thiswould take the form of batteries designed to givethe Brigades stated period of operation. However,various options are available and a choice dependson the period of backup and whether or not otherdevices share the backup source, for example, theGD92 Comms unit. The charging of such batterieswould be by stand alone equipment or perhaps viaone of the units already part of the system. This isdependant in part on individual suppliers and theirparticular approach. Although there is flexibility inthe type of power supply that can be provided, andBrigades may request backup periods less than theMG4 recommendation, suppliers must be in aposition to achieve the 24 hours if requested.

11.2 Encoder

This component of the Alerter carries out the following basic functions:

Provides two way communication, usingMG4 protocol, with the station GD92Comms equipment.


Figure 11.2 MG4 Alerter Transmitter combined with aGD/92 compliant 'Station end' mobilising terminal.

Generates required team fire or test call usingPOCSAG paging protocol. (See Alerters) Upto 3 teams and the combinations of such arecatered for.

Generate paging calls with alpha numericmessaging if required for individual calls.

Control the sending of calls via the transmit-ter and the monitoring of transmitter parame-ters during calls. (See Transmitter.)

Record the operation of team 'off air' moni-tor receivers to determine the transmission ofcorrect call data.

Assemble the monitored transmitter parame-ters and the 'off air' receiver status and pro-duce a message indicating a successful or

failed call and send this to the station GD92Comms unit for onward transmission to con-trol. If the call is a failure the type of failureis also returned.

Provide a considerable degree of configurationin order to be able to replace a faulty encoderat a station with the minimum of delay.

Where stations may overlap from the point ofalerting coverage provision is made for cop-ing with simultaneous mobilisation of the twostations.

It should be noted that although individual manu-factures have to comply with the requirements ofthe MG4 specification they are not restricted fromproviding additional features, either, of their ownidea or at the request of Brigades, subject to thesenot compromising the prime requirements. Asthese vary from manufacturer to manufacturer it isnot intended to include these in this document.

11.3 Transmitter

The transmitter performs the following basicfunctions:

As the paging code specified in MG4 isPOCSAG (Post Office Code StandardisationAdvisory Group) this requires the transmitterto use FSK modulation. The POCSAG codeis referred to in a little more detail underReceivers.

MG4 requires that a minimum of two trans-mitter parameters be monitored during a callnamely forward power and reverse power.

The transmitter must be capable of 25 wattsoutput with the ability to set alarm triggerlevels. As a guide a level of 12 watts (3 dbdown) would set the alarm. The reversepower alarm indicates the efficiency of theaerial and would normally trigger at what istermed a 'voltage standing wave ratio' of 2:1or approximately 0% reduced power trans-mitted.

The allocated frequency for Firefighters alert-ing is 147.8Mhz and used throughout the UK.

A separate frequency allocated to EmergencyServices is often used to provide wide areaofficer paging and on a few occasions hasbeen used for mobilising purposes. This fre-quency is 153.05Mhz

11.4 Alerters

MG4 calls for the use of alerters working to thePOCSAG format which are produced by virtuallyall manufacturers, and uses a 7 digit numericaddress or Ric (Receiver identity code) code.

The Home Office instituted a numbering schemewhereby the last three digits are fixed for eachBrigade. The POCSAG code allows the first fourdigits to range from ()()()() to 1999, a total of 2000codes per Brigade. In the event of a Brigaderequiring more Ric codes, if for instance multi-Riccode alerters are used for officer paging, then theseare available on application to the Home Office.Two Ric codes are normally required forFirefighters alerters but versions with 4 codes areavailable.

Alerters need to be robust and have protectionagainst ingress of moisture and dust. POCSAGpager design is driven by the large area wide pag-ing market demands of companies such as BT andVodapage together with other international serviceproviders. Final design is, therefore, a compromisebetween design requirements, ready availability,and competitive pricing. This results in low costunits which are often cheaper to replace thanrepair.

Firefighters alerters are normally of the 'tone only'type although some have limited display options tohighlight Fire or Test calls. A flashing LED oper-ates on receipt of a call. The use of rechargeablebatteries has virtually disappeared although stillavailable. A limited need for intrinsically safealerters exists, more from the point of view ofequipping Firefighters with such units because ofthe hazardous areas in which they normally workrather than operational reasons. A vibrate option isavailable where the normal workplace is subject tohigh noise levels.

The Alerter is required to sound for a minimum of30 seconds. POCSAG pagers vary in the period of


Figure 11.3 Alerter.(Photo: Multitone)

call generated by receipt of a single call from anMG4 unit and multiple calls are often used toachieve the overall required alerting period. Thishas the advantage of increasing the chance ofreceiving a call as say four calls separated by 12seconds improve the chances of receiving at leastone good call in areas of weak coverage. Alertersare equipped with a call cancel button.


Beeperoutput

Removableclip

Corporate label area

Attachmentlor lanyard

Battery AA

On/cancel/memory recall

Recessedoff button

Mute mode/deletemessage button

Call source indicatorsand pager status display

Lamp alert

Actual size


Chapter 12 - Mobile Data

12.1 What is Data?

In data communications, information is transmit-ted in the form of characters, namely letters, fig-ures, and symbols. The information is representedby binary signals, which are characterised by dif-ferent states. When considered electrically, thesesignals correspond to, for example, tone ON, andtone OFF.

In digital message transmission over radio circuits,the signal elements of the characters are transmit-ted in turn (serially). Figure 12.1 shows the rela-tionship between DC keying and VF keying.

The Fire Service has been using Data at incidentsfor many years in various formats. 'Data' can beinterpreted as telemetry, resource updates, riskinformation, and can be deployed as direct links tocommand and control systems.

Data transmission capabilities and speeds (rates)are dependant largely on bandwidth. The band-width and, hence, capacity, has risen over the yearsand hence typical data rates now are around 9600bits per second (bps), and with developing tech-nology and compression techniques are expectedto rise in the next few years.

Data can be sent both to and from vehicles andused to supplement information held onboard. Thedevelopment of personal computers (PCs) andassociated software/hardware now allow moredata to be stored onboard vehicles.

12.2 History

Resource Availability Status (RAS)

The use of mobile data in the Fire Service began inthe late 1970's when Resource Availability Status

Figure 12.1Relationship betweenDC Keying and VFKeying.


Figure 12.2 Typicaldata transmissionarrangement.

(RAS) was incorporated into some existing radiosystems. The first systems operated at 100 baudand were literally one way only with the acknowl-edgement being a single tone. Further develop-ment enabled these systems to operate at 300 baudwith two way communications.

All systems operated over the speech radio net-work. One of the major problems associated withthis shared voice/data radio channel was that datatones would block speech traffic using the radiochannel. This had the effect of data being receivedbut speech having to be re-transmitted.

Mobile Data

Depending upon the level of traffic, it is some-times better to provided a radio channel specifical-ly for mobile data. This allows a number of differ-ent types of messages to be passed. The first sys-tems went live in 1989 providing a series of ser-vices to the incident. For example:

Mobilising messages (C&C to mobile).

Administrative messages (C&C to Mobile).

RAS messages both directions.

Access to Management Information Systems.

Access to Chemdata central information.

Incident messages (mobile to C&C).

This was the first time it was possible for mobileinformation to be directly input into C&C systems(RAS had been possible earlier) without any Fire

Control personnel action and requiring the ControlRoom staff to change working procedures.

Figure 12.2 above shows a typical data transmis-sion system. The Dispatcher computer interrogatesthe mobile to establish contact and on receipt of anacknowledgement, sends the data as a burst trans-mission. The mobile is able to display and/or printout the received message. The process can alsowork in reverse, with the mobile initiating the call.

12.3 Current Technology

The term 'mobile data' encompasses data sentwhen an appliance is mobilised, available en routeto an incident, or available at an incident.Requirements for the provision of data vary frombrigade to brigade leading to a multiplicity of sys-tem configuration. The main elements of thesevehicle mounted systems are communicationsprocessors, visual displays, printers, keyboards,radio modems, etc.

12.4 Radio Communications

Various options are available for the transmissionof data between mobiles, or from mobiles and/orfixed locations.

Existing Brigade Radio Schemes - It is possibleto transmit data over existing analogue radioschemes, in fact some brigades use this bearer aspart of their mobilising arrangements. Typicaltransmission rates are 1200bps Frequency FastShift Keying (FFSK).

GSM Cellular Telephone - The Global Systemsfor Mobile Communications (GSM) networks

Control Operator PCMobile Printer and Keyboard


Base Mobile

Figure 12 3 Datainfrastructure.(Graphic: Simoco)

Data Infrastructure

Figure 12.3 shows a typical data system infrastructure developed for use byUK Fire Services. Such a system is able to make use of the Fire Station mobil-ising system that already forms part of the Command and Control facility atany Fire Service Communications Control Centre. The mobilising system isconnected to a Data System Controller whose purpose is to control the opera-tion of the radio data system via the Terminal Server. One function of The DataSystem Controller is to transparently convert data into a form suitable fortransmission to the hill top site Radio Modems. The Terminal Server distributesdata to and collects data from the Radio Modems. 'Best hill-top site' informa-tion is stored and continually updated for all mobiles and the appropriate siteused for any communication with a mobile.

It is possible to send general text messages between Control and mobiles aswell as status messages from mobiles to Control.

incorporate both voice and data modes of opera-tion. These networks consist of individual radiobase stations that communicate with the users,each base station forming a cell. In the data modethe system offers a circuit switched, end to endcommunications service and, at present, transmis-sion speeds of up to 9.6K bits per second.

Packet Radio Service - There are several commer-cial packet radio data networks. These networksdeliver data in the form of bursts or packets. Eachpacket contains address information, informationdata and some form of error correction.

12.5 Data on Vehicles

The data available on mobile resources is asdiverse as that held in the office environment.Individual brigade requirements vary from provid-ing limited information held on mobile computers,to being able to access personnel records, buildingplans, status messaging, global positioning, updat-ing the central mobilising system, receivingturnout information and chemical and risk data.

The data available must be current for it to be ofvalue. The provision of many geographically scat-


Figure 12.4 In CabEquipment.(Graphic: Simoco)

In Cab Equipment

Figure 12.4 shows the typical vehicle installation in a Fire Appliance. Thiscomprises two separate mobile radios, including a Voice Radio which can beused for voice transmissions at any time and a separate Data Radio operatingon its own radio channel.

The Data Radio, which would incorporate a modem, would be used to passstatus information, various data, and free text information from a Mobile DataTerminal (MDT) which comprised an in-vehicle PC, Touchscreen Display,Printer and Keyboard. The PC might be equipped with large capacity harddrive memory which can hold map data, chemical data, risk files etc., whichcan be triggered by the incoming data to give information specific to theincident. The Touchscreen gives the mobile operator the facility of manuallyaccessing data, maps etc. or of inputting status or text messages, as required.

The printer makes it possible to produce hard copy of diplaxed data, while thekeyboard max be used for the inputting of text or for maintenance access.

tered mobile data terminals leads to difficulties inmaintaining the data, especially if a large percent-age is held on the terminal. It is essential that arobust and effective system is established so thatupdating the stored information is carried out onall the terminals within a minimum period of time

Part of this process should include an audit trail sothat it is possible at a later stage to verify when andwho amended any of the data files. Various meth-ods have been adopted to carry out this procedureincluding updates by floppy disk, CD ROM, radio

or wire connection to each data terminal when thevehicle is in the fire station.

12.6 Typical Data Requirements

The following data packages are available for useon mobile processors, whether held on the mobile,retrieved from a central source or a combination ofboth. Software licensing issues, along with otherfactors, may influence whether data is held cen-trally or dispersed amongst the mobile terminals.


Touch-screendisplay

Mobile dataprocessor / PC

Data radio

Voice radio

Printer

Keyboard

1 Status Messaging

The ability of the mobile resource to updatethe central mobilising computer of any changeof status instead of using a voice radio or cel-lular telephone scheme. This facility shouldalso incorporate the ability to send other stan-dard messages, for example, assistance andstop messages, and should have a free textoption to cater for any non standard messages.

2 Risk Information

Information gained from the inspection ofpremises, under the relevant section of theFire Service Act, shows the layout of thepremises, the utility supply inlets and isolat-ing points, the location of water supplies andany risks to fire fighting. This data, which hastraditionally been held in paper form, lendsitself to being held electronically, thus mak-ing it available to all mobile data terminalsand centrally on the brigade's own network.Building plans and maps may also to belinked to this risk information.

3 Brigade Information

Brigade orders, fire fighting information,operational and technical procedures, anyinformation produced by Brigades or fromother sources may be held in an easily retriev-able format so that the Officer-in-Charge ofan operational incident has all the informa-tion available.

4 Hazardous Information

Information relating to hazardous substancesmay either be held on the mobile or centrally.Chemdata, for example, when held centrally,can be distributed by radio and only compris-es of a relatively small amount of data.

play individual buildings. These maps canthen be linked to building plans, street mapsare also available to replace the map bookscarried on vehicles.

Hydrant and water main information mayalso be superimposed on the maps so that theinformation resources of the Brigade areavailable to all mobile terminals.

Clearly, mapping data files are quite large.Therefore, storing the maps centrally andtransmitting the data on demand wouldrequire high transmission rates, cause con-gestion on the radio network and be expen-sive. Currently, it would be better to store thistype of information on the mobile data termi-nal hard drive (if available).

6 Automatic Vehicle Locating Systems(AVLS)

AVL systems have been available commer-cially for some years. It has only been morerecently that the Fire Service has investigatedthe technology for its own use (see DCOL8/1997, in Scotland DFM 8/1997).

There are two basic systems in use; landbased and satellite. The vehicle is fitted witha suitable AVLS receiver which, followingthe reception of signals, allows the geograph-ic position to be computed and then transmit-ted to a central mobilising system. The posi-tion of the vehicle is then displayed on a mapat the central control.

These systems have varying degrees of accu-racy but care must be taken when attemptingto predict the precise location and direction ofmovement of a vehicle using this system. It ispossible for example, that the AVL systemcould indicate that a vehicle is located closeto the scene but it transpires that it is on thewrong side of a river or motorway to attendthe incident. (See AVLS, Chapter 7.)

7 Vehicle Telemetry

With the provision of a processor on a vehi-cle and a wireless connection with a central


5 Graphical Information Systems (GIS)

GIS software, which requires mapping data,gives the operational crews access to maps ofthe Brigade area, ranging from 1:5().()()()raster based maps to vector based maps,which enable the operator to zoom in to dis-

point it is possible to send telemetry informa-tion. For example, information on the vehicleengine systems could be routed to theBrigade's transport department or show quan-tities of water, foam or other operational con-sumables to the Control Centre or mobilecontrol unit.

12.7 Mobile Control Units

With the development of reliable data transmissiontechnology and vehicle based computer systems,mobile control vehicles, used for major incidentcommand and control, are now being equippedwith IT systems linked to brigade computer net-works and mobilising systems.

These vehicles include complex computer systemsand voice/data message handling facilities.Bespoke software packages have been developedspecifically for this purpose.



Chapter

13Chapter 13 - Breathing ApparatusTelemetryThere is an increasing need to provide firefighters,particularly those protected with breathing appara-tus, with enhanced information to improve boththeir safety and operational effectiveness. Thisinformation could include, for example, informa-tion on remaining cylinder contents and respirationrates, ambient and body core temperature, heart-rates, etc.

This data can be displayed to the wearer in full, ormore practicably in an abbreviated form, perhapsby means of a display in the firefighter's breathingapparatus facemask. They can also be recorded inan electronic data-base and downloaded at the con-clusion of the incident, to provide a record whichcan be added to personnel records and used in theinvestigation of any injury or malfunction of theapparatus.

It is also possible to transmit some of this data byradio to those controlling the incident, includingthe Incident Commander or the breathing appara-

tus Entry Control Officer where the data can beused to provide information which can be used tofacilitate better control of the incident and toimprove firefighter safety.

The provision of a radio data link between fire-fighters and those controlling the incident will alsopermit the remote signalling of other safety sig-nals, including the transmission of information tothe breathing apparatus Entry Control Officer of amessage in a data format indicating the automaticor manual operation of a breathing apparatusDistress Signal Unit, and the transmission of amessage in a data format causing the operation ofan Evacuation Signal either to all in the risk area orselectively.

It also facilitates the signalling of a radio messagein a data format indicating that the operator iswithdrawing from the risk area for reasons of per-sonal safety. This last information, particularly ifmore than one team signals this, will assist the

Figure 13.1 RadioDistress Signalling Unit.(Graphic: Marconi)

Radio Distress Signalling Unit

Functions as an Automatic Distress Signal UnitIntrinsically safe

Transmits Distress Alarm messageTransmits Withdraw messageReceives Evacuation message

Receives Selective Evacuation messageTransmits Data from external source


Figure 13.2 EntryControl Unit.

(Graphic: Marconi)


Figure 13.3 Telemetry in use during trials.{Photo; Essex Fire and Rescue Service)

Incident Commander in deciding whether emer- based on the use of a dedicated radio frequency ingency evacuation of the risk area is justified. Home Office regulated radio frequency bands,

supported by a Type Approval (MG41) specifica-The Home Office has developed a User tion and a common-air interface.Requirement (JCDD/40) for fire service telemetry

Can communicate with up to 50 RDSUsReceives Distress Alarm messageReceives Withdraw messageTransmits Evacuation messageTransmits Selective Evacuation messageShows status of RDSUsStores event logReceives Data from RDSU

Figure 13.4 Telemetry in use by Breathing Apparatus Entry Control Officer.

This User Requirement specifies the minimumfunctionality for such equipment, which includesremote signalling of Distress, remote signalling ofEvacuation, Selective Evacuation, and signallingthat the operator is withdrawing for reasons of per-sonal safety. It allows the equipment to be com-bined with, and provide the functionality of, anAutomatic Distress Signal Unit. It also allowsconnection by means of a standard interface, andtransmission of data to and from operator-wornequipment providing enhanced functionality suchas cylinder contents, temperature and so on. A sim-ilar connexion is specified for the remote elementof the system to allow the use of equipment formanaging the incoming data.



Chapter 14 - Sub-surfacecommunicationsAlthough there are exceptions, underground tun-nels and similar structures are normally designedfor use for transportation, mineral excavation, car-parking and storage purposes. Apart from under-ground car parks, the structures are often quite oldand, as a result, neither designed or built to idealstandards.

The characteristics of each tunnel or structure willvary greatly, a tunnel may be nothing more than ashort horizontal tube cutting through a hill, or itmay be a vast underground complex with manytunnels, access points and service and customerfacilities. Tunnels under construction will give riseto different problems.

The following applies to any building which isconstructed completely or partially below ground,and includes any tunnel constructed as a railway, aroadway or for any other purpose that might attracta fire brigade attendance. It could include, forexample, service access to large shopping, indus-trial, hospital, office and housing complexes.

For practical purposes there is no penetration ofthe surface by any of the radio frequencies used bythe fire service for normal above-ground commu-nications. Technical Bulletin 1/1993 providesguidance on Operational Incidents in Tunnels andunderground structures and includes, as Part 3,Guidance on Communications in these risks.

In September 1997 the Home Office completedsuccessful trials of a low-cost technique forimproving fire service at-incident UHF radiocommunications. (Trial reports were issued inDCOL 1/1998 Item C, in Scotland as DFM2/1998 Item C.)

The trial comprised a number of self-containedand handheld radio UHF base stations, operating

on one of the UHF two-frequency 'simplex' inci-dent channels on permanent talk-though, and usedin conjunction with fire service standard handheldradios. Any number of such base stations can belinked together by means of a simple audio cableto provide seamless communications. In effect anyhandheld radio within range of one base stationcan communicate with any other handheld radiowithin range of any base station.

The distance between base stations is limited bythe physical length of the connecting cable (100min the trials) and by the maximum radio rangeachievable in the specific risk using UHF handheldradio radios.

Typical coverage using six base stations were:

1150m in a Railtrack tunnel (compared with350m using a single base station). The limitin this case was the length of connectingcables.

810m in a BT cable tunnel (compared with160m using a single base station).

The Home Office has produced a specification,MG49, for this type of equipment to enablebrigades to carry out their own procurement.

In operational use, one base station might beestablished on the surface. A Breathing Apparatusteam would then enter the risk area carrying oneor more additional base stations and the associat-ed connecting cables, deploying a connectingcable as they advance. The first base station auto-matically emits a repeated tone so that the BAteam can discern when they reach the limit ofradio coverage from that base station. At thispoint they can establish a second base station andconnect it to the first base station thus providing

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Figure 14.1 Home Office Repeater Unit.(Photo: Devon Fire and Rescue Service)



Figure 14.4 Sonic UHF/UHF Repeater Unit.{Photo: Devon Fire ami Rescue Service)

continuous coverage from the surface to beyondthe second base station.

The team can then proceed further into the riskarea, deploying further cables and base stations asnecessary. Each base station would transmit aunique identity tone.

A technical disadvantage of this method of deploy-ing the equipment is that it does not maximise therange achieved because it ignores the potentialadditional coverage which can be achieved when asecond (or subsequent) base station is deployed,


i.e., the second base station, once connected andactivated, will provide its own coverage area.Using this method of deployment coverage willoverlap that already achieved from the first basestation. There is also the possibility of quasi-syn-chronous interference beats.

The foregoing arrangements can be improved byestablishing 'ideal' locations for base stations aspart of incident pre-planning. Connecting cablescould be pre-laid and base stations could even beinstalled at appropriate risk sites.

Multi-way Socket at rear of the Unit allowsadditional Units to be connected in series via an

Audio Cable

Stub AerialOn/Off Switch

Multi-way SocketCarrying Handle

Green light indicates

Stub Aerial

Red light indicates repeaterswitched on

On/Off SwitchCarrying Handle

Audio Cable connectedto repeater

Chapter 15 - Potential hazards of usingradio equipment

IN FLAMMABLE ATMOSPHERESNEAR EXPLOSIVES OR INHOSPITALS

15.1 Explosion Protection •Standards

Special precautions are necessary when working inareas where a potential ignition or explosion haz-ard exists. These could be due to the presence offlammable dusts, gases or vapours, such as in oilrefineries, petrol storage depots, some factoriesand commercial premises, coal mines, etc. Theintroduction of electrical or electronic equipment,such as a radio, by firefighters to such environ-ments may constitute an ignition hazard.

Where such environments are known to exist, orare suspected, then the electrical equipment needsto be safe for such use. This means that suchequipment should be designed in such a way that itdoes not present a hazard and that it should be cer-tified accordingly. There are a number of designconcepts for achieving this of which the most com-mon for radio terminals is that of 'IntrinsicSafety'. Any equipment designed to be safe insuch environments is generically described as'explosion protected'.

Additional precautions are also necessary whenusing radio transmitters in the vicinity of explo-sives, ignition hazards or other devices that may beadversely affected by radio transmissions. Thissection deals in some detail with the technicalaspects of terminal equipment to be used in poten-tially flammable dusts, gases or vapours. It con-cludes by giving operational advice and guidanceon precautions to be taken by firefighters whenusing radio transmitters in potentially flammableor explosive atmospheres and use of radio in thevicinity of explosives, petrol stations and medicaldevices.

In the European Union (ELI), standards for electri-cal equipment designed for use in flammable gasesand vapours are those approved by the EuropeanCommittee for Electrotechnical Standardisation(CENELEC). Such equipment may be certified asmeeting the relevant standard by an EU approvedCertification Body. The relevant EU standards forIntrinsic Safety are drawn from EN50 014, EN50020 and EN50 039.

Terminal equipment in current use in the fire ser-vice may have been manufactured to comply withan earlier standard, e.g., British Standard 1259,1958 or a BASEEFA standard SFA 3012 1972. Thisequipment can continue to be used until replaced.

Outside the EU other standards exist. In particular,in the USA and those parts of the world whereUS standards prevail, equipment is certified to stan-dards specified by either Underwriters' Labaratoriesor Factory Mutual Research Corporation.

For the UK fire service the recommended standardfor general applications where a potential ignitionhazard exists is for equipment that is certified foruse in Zone 1 with gas group IIC and a maximumtemperature rating of T4. Such equipment wouldbe indelibly marked EEx ib IIC T4 (or T5 or T6).It is also recommended that such equipmentshould satisfy a degree of ingress protection of atleast IP54 to EN60 529.

It is recommended that radio equipment purchasedfor use with breathing apparatus should, as a min-imum, conform to this standard. The equivalentUS standards are Underwriters' LaboratoriesUL913 or Factory Mutual Class No 316.



15.2 Ignition Sources

The presence of radio terminal equipment in apotentially explosive, or flammable, dust, gasor vapour can give rise to a number of possiblehazards from which ignition might result.These include overheating of the radio terminalduring use or, more likely, during fault condi-tions. In modern mobile radio terminals fromreputable manufacturers this is most unlikelyto occur under any working conditions whenthe equipment is fully serviceable and operatedcorrectly.

The other potential dangers from the use of radioterminal equipment arises from the possibility ofsparking. Sparks of sufficient energy to cause igni-tion may be produced by two quite distinct mech-anisms, as follows:

(1) Sparking may occur when contacts are madeor broken in circuits carrying electric cur-rents, or containing sources of electricalenergy; and

(2) Whenever a radio transmission is made theelectro-magnetic field radiates radio frequen-cy voltages in all conducting materials in thatfield. The induced voltages in adjacentconducting elements, or between conductingelements and 'earthy' conductors, may besufficient to break down intervening insulat-ing layers of oxidation, grease, air, etc., andcause dangerous sparking. This hazard isdirectly related to the nature of the environ-ment, the characteristics of the transmission(power, type of modulation, etc..) and the dis-tance of the antenna from the hazard.

15.3 Protective Measures

Fire service mobile radio terminals (with anexpected transmit power between 5 Watt and25 Watt) potentially introduce all of the hazardsdescribed in paragraph 3 above into the risk envi-ronment. There is also a potential risk that theantenna of a vehicle mounted radio may directlytouch a conductor during transmission causingsparks.


When transmitting, they may also introduce arisk of inducing a current in a conductor, causingremote sparking and ignition or some otherunwanted consequence.

The risk from any 'fixed' mobile radio terminalequipment should be minimal since it is expectedthat any potential hazard should have alreadytaken into consideration before siting is decided.However, some brigades employ transportable ter-minal equipment which may be used, for example,as temporary controls or talk-through stations forspecial purposes. Such terminal equipment gener-ally has transmitter power of 5-25 Watts and,therefore, the potential risk is comparable to that ofa vehicle installation but it may be used in loca-tions inaccessible to vehicles. This category ofequipment should not be overlooked in any hazardassessment or the drafting of relevant orders.

For relatively low-powered handheld radio termi-nal equipment (typically less than lWatt) the max-imum radiated power is usually insufficient to cre-ate induced currents in adjacent conductors.Potential ignition hazards with handheld radio ter-minals are, therefore, limited to the developmentof dangerously high temperatures, and sparkingcaused by making or breaking electrical circuits.High temperatures are only likely to exist in faultconditions, e.g., by a component failure or break-down of insulation and steps can be taken to pre-vent internal sparking that has sufficient energy toignite a flammable or explosive dust, gas orvapour.

Thus, it is a practical proposition to design anhandheld radio terminal which can be used withsafety in a potentially hazardous environment, i.e.,explosion protected equipment. Explosion protect-ed terminal equipment nearly always exists as wellin a normal, un-protected form. In comparisonwith the non-protected terminal equipment theprotected equipment will often have a reducedmaximum transmitter power, be more expensive toprocure and maintain, will require 'special' batter-ies and may have reduced functionality.

The selection of protected types of handheld radiois also likely to be much less than un-protectedtypes and purchasers may have a limited choice ofequipment from which to select equipment for pro-curement.

15.4 Intrinsically Safe DesignCriteria

The requirement for explosion protected equip-ment certified for use in flammable, or explosivedusts, gases or vapours, means that the equipmentmust be incapable of causing ignition, even underfault conditions or when subjected to gross mis-handling. This necessitates design features whichoften have performance penalties in normal condi-tions.

It is usually necessary, for example, to make itimpossible for batteries to be fitted or removedwithin the hazard area, because of the potentialdanger of sparking during this process. Therefore,it is usual for the battery compartment of suchequipment to be fitted with a key-operated lock so

that compartment can be locked and the keyretained outside the hazard area. In ordinary firebrigade use such a fitting may be an inconve-nience.

To obviate the possibility of components over-heating, current limited devices (often resistors)have to be fitted which may reduce performance.Extra thermal insulation may have to be provid-ed, making the equipment more bulky than itwould otherwise have been. The mandatory dis-tance separations of components, and conductorson printed circuit boards, may also affect equip-ment size.

Requirements for special materials or plating, nec-essary to withstand long-term exposure to certainchemicals, involve considerable additional cost; asdoes the incorporation of all the other non-stan-dard requirements mentioned. These are some ofthe factors which combine to make the idea ofusing this equipment for all purposes quite unat-tractive both from size and costs.

15.5 Selection of ExplosionProtected Equipment

The current recommendation to the fire service isthat radio equipment purchased for use withbreathing apparatus should be certified by an EUapproved Certification Body for use in Zone 1with gas group IIC and a minimum temperaturerating of T4. Such equipment will be indeliblymarked as follows:

EEx ib IIC T4 (or T5 or T6)

Certified equipment must cater for worst-case con-ditions for the whole of its working life under con-tinuous operation in a hazardous environment. Itmust also take into account carelessness, clumsi-ness and ignorance on the part of the operator.

In perspective, the few occasions when faults willdevelop in modern personal radio sets are consid-ered and the fact that fire service personnel aretrained to comply with instructions regarding careof this equipment, the occasions when all theabove special design features would be needed issmall.


15.6 Radio Use in the Vicinity ofExplosives, etc.

Radio transmissions impose a potential ignition orinitiation hazard near commercial explosives, mil-itary ordnance (including nuclear weapons) andterrorist devices.

In this context, many modern radio terminals,forexample, data capable radios, 'trunked' radios andradios using public cellular or public data servicesare capable of auto-transmission. Unless the trans-mission function can be inhibited by the user suchequipment should be switched off if it is necessaryto take it into the protected area appropriate for thetype, e.g., if it is necessary to take a public cellularradio terminal to within 10m of the hazard.

15.7 Radio Use in Vicinity of RetailPetrol Stations, etc.

Current guidance to the fire and police services isthat similar restrictions to those applicable to theuse of radio terminals in the vicinity of explo-sives should be applied in respect of retail petrolstations, petroleum transfer stations and oildepots.

15.8 Radio Use in the Vicinity ofAir Bags

Because of the potential, but remote, danger ofactuating an air bag in a vehicle which has beeninvolved in a road traffic accident in which an airbag has not actuated, no radio terminal should beused to transmit a message within 10m of thevehicle.

Additionally, to avoid the remote possibility ofunwanted actuation, no handheld radio terminal orhandheld cellular radio terminal should be usedinside a vehicle equipped with an airbag unless itis connected to an aerial system external to thevehicle.

15.9 Radio Use in the Vicinity ofMedical Devices

There is a potential hazard that radio transmissionsmay have unwanted effects of medical devices.

No fire service handheld radio can be consideredas being safe to use in radio sensitive areas of hos-pitals, nor can any 'safe-distance' be recommend-ed. Accordingly, handheld radios should only beused for transmission in hospital buildings inexceptional circumstances and where the circum-stances are unavoidable. If a handportable radiohas been used then this should be reported locallyto the hospital/medical staff so that they can initi-ate whatever checks they might think necessary todetect and rectify any effect that the transmissionmight have had.

In this context, many modern radio terminals, forexample, data capable radios, 'trunked' radios andradios using public cellular or public data servicesare capable of auto-transmission. Unless the trans-mission function can be inhibited by the user, suchequipment should be switched off if it is necessaryto take it into a hospital premises.

Where a hospital has placed a restriction onthe public use of cellular radios then theserestrictions should also be taken as applying tohandportable radio terminals or any publiccellular radio terminals that may be used byfirefighters.


Current guidance to the fireand police services is that noradio transmitting equipmentshould be used within 10m ofthe risk, that only handheldterminal equipment (less than5 Watt) should be used within10m and 50 metres, and thatvehicles fitted with mobileradio terminals should notbe taken within 50m of therisk unless the radio isswitched off.

15.10 Radio Use within Silos

The presence of a radio may cause ignition of anyflammable dust, gas or vapour that exists in a silo.There is also a remote possibility that a transmis-sion from a handheld explosion protected (intrinsi-cally safe) may result in a spark caused by aninduced current.

Notwithstanding the foregoing, the Officer-in-Charge may decide to permit the limited use ofexplosion protected (intrinsically safe) hand-held radios or telemetry equipment within asilo, provided that a risk assessment has beencarried out and it is considered that the opera-tional and safety benefits of so doing exceed theremote risk of ignition.


Accordingly, similar restrictionsto those applicable to the use ofradio terminals in the vicinityof explosives should apply tothe use of radios near or withinsilos until it has been establishedby monitoring that there is notrace of a potentially flammabledust, gas or vapour withinthe silo.


Glossary of terms and abbreviations

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Address Point

Alerter system

Algorithm

Analogue

ACD

AFA

AVLS

BA Interface

Bandwidth

Base Station

CACFOA

Call sign

CCTV

Cellular

Ordnance Survey digitally co-ordinated postal address data.

A call-out system utilising pocket-alerters, carried by retained firefighters,which are triggered by a radio signal transmitted by a remotely controlledalerter transmitter usually located at a fire station.

A procedural model used when computing complicated calculations(e.g., routes and drive times).

An analogue signal is one which can vary continuously, taking any valuebetween certain limits. The human voice, for which the public telephonenetwork was designed, is an analogue signal varying in frequency andvolume.

Automatic Call Distribution.

Automatic Fire Alarm.

Automatic Vehicle Location Systems.

An interface designed to permit a handheld radio set to be used in con-junction with breathing apparatus.

The range of signal frequencies which can be carried by a communicationschannel subject to specified conditions of signal loss or distortion.

The transmitter/receiver and associated equipment at a fixed location.

Chief and Assistant Chief Fire Officer's Association.

An identifier, normally comprising a name, numbers or letters, by whichan appliance or officer is identified when being called by radio.

Closed Circuit Television.

A technique used in mobile radio telephony to use the same radio spec-trum many times in one network. Low power radio transmitters are usedto cover a limited area or 'cell' so that frequencies in use can be re-used inother parts of the network.

CHEMET

CIMAH

CLI

Concentrator

COSHH

CTCSS

Cycle

DCOL

DDI

DIEL

Digital

Digital data network

DTI

Duplex working

EAs

EACC

ERP

ESM

ETD

ETSI

Fire alarm call point

Chemical Meteorology.

Chemical Incident Major Accident Hazard.

Calling Line Identity.

Any communications device that allows a shared transmission medium toaccommodate more data sources than there are channels currently avail-able within the transmission medium.

Control of Substances Hazardous to Health.

Continuous Tone Controlled Signalling System. In PMR, a method ofusing sub-audio tones to effect selective transmissions to a mobile orgroup of mobiles.

The portion of the radio wave between successive crests or troughs, whichis repeated over and over again to form the continuous wave.

Dear Chief Officer's Letter.

Direct Dial In.

OFTEL's advisory committee on telecommunications for Disabled andElderly People.

Communications procedures, techniques and equipment where informationis encoded as either a binary ' 1' or '0' .

A network specifically designed for the transmission of data, whereverpossible, in digital form.

Department of Trade and Industry.

A communications technique in which it is possible to transmit andreceive simultaneously e.g., as in an ordinary telephone conversation.

Emergency Authorities.

Emergency Authority Control Centre.

Effective Radiated Power.

Emergency Services Manager.

Extension Trunk Dialling Network.

European Telecommunication Standards Institute.

A device to operate the fire alarm system manually.


Fire alarm system

Frequency

FFSK

FMG

FRNT

Geocode

GIS

GPO

GPS

GSM

GTPS

Handshake

Hertz (Hz)

Hilltop Sites

HOFMG

ICCS

ICU

Inmarsat

A fire alarm system comprising components for automatically detectingfire initiating an alarm of fire and taking other action as arranged. The sys-tem may also include manual call points.

The number of cycles of wavelengths, which appear to pass a given pointin a specified time, usually one second.

Frequency Fast Shift Keying.

Frequency Management Group.

Front Office Directory.

Assignment of a specific grid reference to an incident, address orrendezvous point, etc.

Graphical Information Systems.

General Post Office.

Global Positioning System - Navigation system developed by the UnitedStates Defence Department as a world-wide navigation and positionresource for both military and civilian use. It is based on a constellationof twenty four satellites orbiting the earth at a height of over 20,000kilometres. These satellites provide accurate three dimensional positionand velocity as well as precise time, and act as reference points fromwhich receivers on the ground triangulate their position.

Global Systems for Mobile communications - European standard for digi-tal cellular networks operating at 900 MHz world-wide and supportingdata transmission.

Government Telephone Preference Scheme.

A predefined exchange of signals or control characters between twodevices that sets up the conditions for data transfer or transmission.

Measurement of frequency where one Hertz equals one cycle per second.

Or Main Stations are normally on high, open ground (hence the alterna-tive name) from which it is possible to 'see', in the radio context, a con-siderable portion of the brigade area. 'Main' equipment operates in an'omni-directional' mode to cover the largest possible geographical area.

Home Office Frequency Management Group.

Integrated Communications Control System.

Incident Control Unit.

International Maritime Satellite Organisation.


Interface

IS

ISDN

KiloStream

LAN

Leakv feeder

Link Transmitters

Main scheme radio

Main Control

Main Transmitters

'Mobiles'

MIS

MMC

Modem

Multi-station scheme

NOU

A shared boundary, a physical point of demarcation, between two deviceswhere the electrical signals, connectors, timing and 'handshaking' aredefined. The procedures, codes and protocols that enable two entities tointeract for the meaningful exchange of information.

Intrinsically Safe Equipment designed to be operated safely in an environ-ment consisting of flammable or explosive dusts, gases or vapours.

Integrated Services Digital Network - An internationally agreed publicnetwork offering switched end-to-end digital services for voice and data.

The registered trademark for BT's digital network services, used forconnecting a variety of high-speed applications including computers,LAN interconnect and switchboards.

Local Area Network is one which spans a limited geographical area,usually within one building or site, and interconnects a variety ofcomputers and terminals, usually at very high data rates.

A linear aerial which radiates radio signals throughout its length. Suchan aerial is particularly suited to facilitating radio communications insub-surface premises in conjunction with a UHF base station.

And Link Receivers provide communication between the control stationand the main stations. 'Link' equipment operates in a 'Point-To-Point'mode in which every effort is made to send signals only in the intendeddirection and only so far as necessary.

A radio system giving wide area radio coverage throughout the areacovered by the mobilising control.

'Control Station' or simply 'Control'. This is the place where theoperators who control the scheme, and the main transmitting andreceiving equipment of a scheme are located.

And Main Receivers send radio signals to, and receive radio signals from'mobiles'.

Are the transmitter/ receivers fitted in fire appliances and othervehicles.

Management Information Systems.

Monopolies and Mergers Commission.

Modulator/Demodulator - device for converting analogue signals intodigital signals and vice-versa.

A scheme served by several main stations e.g., a large country scheme.

Network Operations Unit.


OAC

OFTEL

Out-stations

PABX

PCNs

PCS

PDA

PECS

PMR

POCSAG

Private wire circuit

Protocol

PSTN

PTO

Public Address

PWIT

RBRT

RIC

RIDDOR

RFCPU

Roamer

Roaming

Operator Assistance Centre.

Office of Fair Trading for Telecommunications.

All radio stations in a scheme, including two-way fixed and mobile setsand fixed receivers but excluding main stations, main and sub-controls.

Private Automatic Branch Exchange.

Personal Communications Networks.

Personal Communications Systems.

Pre-Determined Attendance.

Public Emergency Call Service.

Private Mobile Radio - A network developed for one particular organisa-tion, usually an emergency service.

Post Office Code Standard Advisory Group

A dedicated telephone circuit permanently connected between two or morepoints for transmission and reception of speech and/or data.

A set of rules governing information flow in a communication system.

Public Switched Telephone Network.

Public Telecommunications Operator.

A loudspeaker system which may be operated by remote control from a cen-tral control room or locally for both operational and administrative purposes.

Public Warning and Information by Telephone.

Racal BR Telecoms Ltd.

Receiver Idendity Code.

Reporting of Injuries, Diseases and Dangerous Occurrences.

Radio Frequency and Communications Planning Unit.

Is the term used to describe a person who takes their mobile phone abroadwith the specific purpose of making or receiving calls.

Is is the term used to describe the ability for a person to take their mobilephone abroad and be able to make and receive calls in a country withwhich their own network operator has signed a roaming agreement.


Running call facility

Secondary Control

Simplex working

Single frequency scheme

SMS

Switch

Talk-through

Telemetry

Terminal

TODS

TOPS

Transportable Radio

TUES

Two-frequency operation

UHF base station

WAN

WARC

Wavelength

A facility at a fire station which enables a running caller to give an alarmof fire.

A mobilising control (possibly in another fire brigade area) to which, inan emergency, the functions of receiving emergency calls and mobilisingappliances are passed, in the event of an evacuation of the normalmobilising control.

A communication technique in which it is not possible to transmit andreceive simultaneously.

A scheme using one common frequency for transmitting and receiving byall stations.

Short Message Service.

A switch is the core element of a radio or telephone system. It providescontrol, management and the routing of voice and/or data calls betweenradio system infrastructure, mobiles and portables, telephones, controllersand computer terminals.

A facility on two-frequency radio schemes which interconnects incomingand outgoing channels. Used to enable out-stations on a scheme to hearand talk to each other.

A means of establishing measurement remotely.

A device for sending and/or receiving data on a communication channel.

Telephone Operator's Directory System.

Total Operations Processing System.

A portable transmitter/receiver of roughly the same power as a mobile set.

Text User's Emergency Service.

A means of operation whereby radios receive on one frequency and trans-mit on a different frequency (also known as double-frequency peration).

A radio installation which allows boosted signals of double frequencyoperation with UHF equipment. This equipment is usually provided as amobile version but. exceptionally, e.g., at major airports, there are autho-rised fixed installations.

Wide Area Network - Interconnects geographically remote sites.

World Administration Radio Conference.

The distance between successive crests, or successive troughs.



APPENDIX 1

Control Staff - Training, Competenceand PromotionFire Authorities have a legal duty to ensure per-sonnel are adequately trained. The FireServices Act of 1947 Section 1(1) states "EveryFire Authority shall secure... the efficient train-ing of the members of the Fire Brigade".

Training should be appropriate to the position heldand must develop and consolidate the skills,knowledge and attitude of personnel to allow themto deal with a wide range of situations both effi-ciently and safely.

The ever increasing number of emergency calls,and increased managerial controls, have createdgreater training needs, not only for operationalfirefighters but also for Control Personnel.

The need for this training can be broken downinto:

Training required to maintain the operationaleffectiveness of Control Centre Personnel.

Training recommended by the Home Office.

Training essential to fulfil responsibilities inrespect of legislation i.e.. Health and Safety,Equal Opportunities.

Training desirable to enhance the profession-alism of Fire Brigade personnel.

The combination of these four areas generate therequirements for training throughout the Brigade.The following strategy identifies all trainingrequirements and sets out the provisions andguidelines to comply with these requirements.

Through training of personnel, the Brigade willrespond to the needs of those it serves by definingtraining needs and providing the most effective

means of fulfilling those needs, thereby providinga quality service.

Training for control personnel has always beenhindered by the small numbers of staff available,and the need to maintain cover in the ControlCentre. Training is usually watch related and car-ried out at the normal place of work, this ensuresthe maximum number of personnel available. Forthese reasons Brigades should consider the provi-sion of a Training Officer, and/or Watch trainingdays away from control.

Operator Training should ensure that potentialproblems for the Operator are kept to a minimum,the emphasis on call-handling training needs toaddress primarily the issue of how to handle anindividual caller and what precisely to say tocallers, especially those who appear to be in dan-ger.

At all times the operator must:

Listen - do not make assumptions.

Be firm but polite.

Be in control - interrupt callers if necessaryto ask questions.

Keep questions simple and unambiguous.

Repeat address details to confirm they arecorrect - care should be taken not to do this'parrot fashion' or at the same speed as typ-ing. This sounds very inefficient and does notinspire confidence.

Reassure the caller when necessary but do notstate that the Fire Brigade is 'on the way'until sufficient information has been obtained


for crews to locate the incident. Informing acaller that appliances are en route mayprompt them to hang up prematurely andresult in a delay locating the incident.

Remain calm, do not reflect panic or anger.

Keep the tone of voice normal, even if havingto speak louder.

Speak clearly.

Be prepared to rephrase questions to obtaindetails.

Do not use Fire Brigade terminology.

Do not hesitate, or tell the caller to 'hold on'or'bear with me' or use any other phrases orslang that may indicate lack of confidence ornot being in control of the situation.

The techniques involved can be broadly cate-gorised as 'reactive' or 'pro-active'. The operatorcan be entirely reactive if the caller provides thenecessary information in the correct order andwithout prompting.

What is much more likely is that the caller will atthe very least need to be prompted, particularly toprovide the required information in the order need-ed to complete the call taking screen-format. Suchan approach is both reactive because it responds tothe caller and pro-active in the sense that it takessome measure of control over the human interface.

Where the caller is in danger, however, theremay be a need to adopt a fully pro-active tech-nique by:

Providing relevant fire safety advice aimed atminimising the hazard to the caller; and

Providing reassurance to the caller.

Fire Control Operators should have some basicknowledge of fire survival techniques. The firstpriority must always be the mobilisation of appli-ances followed by the standard fire safety advice -

"GET OUT AND STAY OUT".


Only when the caller or the situation clearlyrequires further intervention by the Operator toenable survival should additional guidance beoffered. This guidance should be limited to stan-dard fire survival advice suitably adapted to thesituation, following an assessment based on infor-mation obtained from the caller.

The details obtained from a caller have to be asinformative as is necessary to enable crews tolocate incidents as quickly as possible. A fewextra seconds questioning the caller may saveminutes in actually locating the incident.

Full guidance on 'Training in Emergency CallHandling Techniques and Fire Survival Guidance'is contained in the Fire Control Personnel Trainingpackage issued to complement Fire ServiceCircular 10/1993.

Training recommended by the Home Office is pro-mulgated to brigades through courses at the FireService College or as Fire Service Circulars, whichrecommend a framework from which individualfire authorities can compile their own training pro-gramme.

Many of the recommendations in FSC 2/1987remain valid. However, further (and updated) rec-ommendations are made in FSC 10/1993.

Fire Service College Courses

(Photo: HM Fire Service Inspectorate)

Currently there are three courses specificallyfocused on Control Personnel.

The needs of individual fire brigades will betaken into account when selecting candidatesfor courses at the Fire Service College.

Junior Control Room Course

Operators who through appraisal have beenidentified as benefiting from attendance.

Operators who have passed an internal pro-motion examination to Leading Fire ControlOperator.

Leading Fire Control Operators and SeniorFire Control Operators who have not previ-ously attended the course.

Senior Control Room Course

Leading Fire Control Operators who havesuccessfully completed the Junior ControlRoom Course.

Leading Fire Control Operators who havepassed an internal promotion examination toSenior Fire Control Operator.

Leading Fire Control Operators, Senior FireControl Operators and Fire Control Officerswho have successfully completed a JuniorControl Room course, preferably within oneyear of promotion.

Control Management Course

Fire Control Officers or their deputies whohave, or may have, responsibility for runningthe brigade Control Centre, who have suc-cessfully completed a Senior Control Roomcourse.

Refresher training

Refresher training may also be available forpersonnel who have not attended a course atthe Fire Service College for five years.

Brigade Based Initial RecruitTraining

All recruits should be given a one or two dayinduction course which should include informationon Health & Safety, Equal Opportunities,Representative Bodies, sickness reporting andleave entitlement. This is followed by a training

APPENDIX 1

course lasting a minimum of three weeks whichmay consist of classroom day duties. During train-ing the recruit should be considered non-opera-tional.

The recruit should be issued with training notes forguidance, and the use of personal training recordsis recommended. On completion of the course theprobationary Control Operator must be able todemonstrate possession of the following coreskills.

A basic knowledge:

of the correct use of items of equipment inuse within the Control Centre including callhandling, mobilising, message and radiofacilities;

of the information required from emergencycallers;

of mobilising requirements for types of inci-dents;

of the Fire Services Acts 1947 and 1959;Sections 1,2, 12, 30, and 31; and

of completing incident statistics.

A working knowledge:

of all callsigns and locations of mobileresources within the Brigade;

of the methods of alerting resources andmobilising to an incident;

of the Fire Service (Discipline) Regulations1985 and the ability to respond positively in adisciplined environment; and

the ability to understand, implement and rep-resent the Brigade's equal opportunities poli-cy in all dealings with members of the publicand employees of the Brigade.

The probationary period may differ from brigadeto brigade but, on completion, it is recommendedthat a final interview be held to discuss perfor-mance and career development.


APPENDIX 1 continued

After the recruit has been attached to a Watch,Continuation Training should be carried out pro-gressively with the aim of improving skills andknowledge gradually. This may take the form of'Competency based' training.

Fire Control Operators should be tested at variousstages of their employment.

Training should continue until, in the third year,Operators consolidate the training received during,and since, the completion of their probationaryperiod to prepare them for the Fire ControlOperator's Qualifying Test.

The test, taken after completion of between 3to 4 years service, should comprise threeparts - oral, written and practical, the detailsof which are in FSC 10/1993.

A fully qualified Fire Control Operatorshould demonstrate the following skills

All core skills as detailed in recruit fire con-trol operator; and

A working knowledge:

of all mobilising procedures at all incidents,and the ability to apply them;

of advice to give to callers in emergency sit-uations;

of specialised mobilising procedures applica-ble to the brigade e.g..

Cave, mine and pothole incidentsTunnelsSpate conditionsFires at seaIncidents involving cylinders

of the location, and mobilising procedures, forall Fire Brigade equipment and appliances,and the location of neighbouring stations;

of topography throughout the Brigade areaincluding special risks;

of initiating appliance standby moves whendirected to do so by the OiC;


of chemical retrieval systems and the passingof chemical information to crews at the sceneof an incident;

of the Central Risk Register and its uses;

of the use of special appliances throughoutthe Brigade;

of the construction, correct use, maintenanceand standard tests off all items of equipmentin use within the Control Centre;

of all control 'fallback' procedures includingsecondary control;

of fault reporting procedures and recordingand amendments to fault records;

of Health and Safety legislation particularly:COSHH, NAMOS, CIMAH, RIDDOR, espe-cially where they effect Fire Brigade opera-tional or control personnel;

of accident/injury reports completed bycontrol;

of the Fire Services Act 1947/1959, Sections2 and 12;

of Conditions of Service with special refer-ence to:

Leave EntitlementSickness ProcedureDuty SystemsDetached Duty ProcedureGrievance Procedure

of the word processor and other software pro-grams in use and the completion and distrib-ution of MIS reports, where applicable;

of the Brigade administrative procedures,control records and filing systems;

of the control business plan and the Brigadeplan, where applicable;

of stores requisitions and goods/servicesreceived.

A comprehensive knowledge of Brigade organi-sation, including:

Brigade line of commandBrigade/Divisional organisationControl management and responsibilitiesSupport services.

of completing incident statistics; and

the ability to complete project work and indi-vidual administrative references as detailedby the Watch Officer having received specif-ic tuition as required.

As the operator progresses through theranks many other skills are required.

(See core skills in Fire Control Centres section.)Some examples of these are listed below.

Officers should show the ability to:

fulfil all obligations appropriate to rank andposition;

supervise and assist control operators;

impart knowledge to others;

apply the Fire Service (Discipline) Regu-lations 1985 as a Supervisory Officer;

apply conditions of service including welfareand health & safety as a Supervisory Officer;

communicate effectively;

design, programme, run and monitor effec-tive training programmes commensurate withBrigade policies, procedures and standards;

give effective support and guidance to Watchpersonnel in career development;

give effective support to the Watch Officer; and

undertake watch reference administrationduties which may include the following:

Command and Control budgets

Training records, schedules and infor-mationStatisticsSuppliesCentral Risk Register/database.

Officers should have a working knowledge ofthe following:

good leadership practices in relation to thesupervision of personnel and support of man-agement;

the financial implications of managementdecisions made at watch level;

the financial implications of managementdecisions made at Control level; and

theoretical and practical aspects of personnelmotivation and welfare.

Watch Refresher Training

In addition to the basic core skills training allControl Personnel should undergo continuous on-watch refresher training. This training will be car-ried out on a systematic basis, both scheduled andmonitored. The subject matter will depend on localcircumstances with emphasis being placed on littleused procedures.

Familiarisation Training

Control Personnel returning from absence throughsickness, injury or maternity leave of three monthsor more should undertake familiarisation trainingto update them on Brigade procedures and toensure the individual's competence in carrying outthe core tasks.

Appointment and Promotion ofControl Personnel

The Fire Service Appointments and PromotionRegulations (SI 1991/369) do not apply to person-nel who are recruited specifically for control cen-tre work. At present, standards for appointmentsand promotion for these staff are matters for indi-vidual fire authorities. On applying for a positionas a Fire Control Operator, prospective recruits are


APPENDIX 1 continued

generally required to pass an elementary educa-tional test set by the fire authority. If successful,the candidate will attend an interview followed bya medical examination.

Promotion is by selection with most local fireauthorities establishing their own standards andpromotion examinations for the purpose. Careerdevelopment prospects for control personnel arenecessarily limited because they are employed inrelatively small numbers.

To determine the qualities needed as to the suit-ability for promotion to higher ranks prospectivemembers of staff should receive personal develop-ment training. This training is normally carried outby individual fire authorities or centrally at theFire Service College as part of a national syllabusfor the more senior posts.

Standards of Competence

A Strategic Document on Standards ofCompetence for Control Centre Staff wasissued to Brigades in October 1997.

Standards of Competence were produced by asteering group comprising of experienced controlpersonnel and drawn from brigades representingthe variations of size, risks, geographical make up,etc., in the UK. The Standards of Competenceshould be used by all control staff to evaluate theirown performance and to identify personal devel-opment needs.

The Standards of Competence were accredited bythe National Council for Vocational Qualifications(NCVQ) at Level 3 in the national framework andhave been made available to Brigades by the FireServices Awarding Body (FSAB).

The National Council for Vocational Qualificationsis now known as the Qualifications and CurriculumAuthority (QCA).

The National Vocational Qualification providesthe first national qualification which has beenspecifically designed for fire brigade control per-sonnel. Brigades who do not wish to introduceNVQ's can still use the Standards of Competencebased training.

Training for competence enables everyone in theControl Centre to demonstrate, through a systemof assessments, against the prescribed standard,that they can consistently and competently per-form their work - embracing the 'safe person con-cept'.

Training for competence provides a frameworkthat offers:

A systematic method of managing and organ-ising the development, delivery and evalua-tion of the control personnel training provid-ed by the brigade.

An objective assessment process that can beused to consistently measure the acquisitionof knowledge, skills, attitude and understand-ing achieved by personnel and teams.

An objective assessment process that can beused to measure, consistently and continu-ously, the application of knowledge, skills,attitude and understanding performed by per-sonnel and teams in the workplace.

Brigades can use the functional outcomes con-tained in these standards to 'role-map' the workand training needs of all watch related control per-sonnel. In total there are 22 functions and 57 ele-ments used to describe the full range of work car-ried out by control personnel.

Training provided for control personnel should bestructured, and delivered, to provide each individ-ual with the knowledge, skills and attituderequired to fulfil the functions contained in theirrole-map. Once the individual has demonstratedthat she or he can perform to the standarddescribed in the functional outcomes she or he canbe described as competent in acquisition.

In order to ensure that competence is continuouslyand consistently being applied, a process of contin-uous work place assessments should be provided.Assessments should be conducted by Watch officerswho should routinely assess their staff to ensure thatthere is a consistent demonstration of competence.

The Standards of Competence should be used forthis purpose and, if training needs are identified,


the individual should be given the necessary train-ing, guidance and support. Control personnelshould also have access to a library of trainingmodules that detail the learning outcomes requiredfor control related subjects or functions.

Control personnel managers at all levels shouldalso be part of a process of continuous assessmentof their role conducted by their line manager(s).

Further guidance on training for competence iscontained in the competence framework (FireService Circular 15/1997).

APPENDIX 1


APPENDIX 2

List of relevant DCOLs/DFMs(in Scotland) and FSCsDCOL DFM

4/1988 = 5/1998

6/1992 = 4/1992

4/1995 = 4/1995

6/1995 = 5/1995

8/1995 = 6/1995

6/1996 = 6/1996

9/1996 = 8/1996

8/1997 = 8/1997

1/1998 = 2/1998

FSC3/1975

FSC15/1997


Acknowledgements

HM Fire Service Inspectorate is indebted to all who helped withthe provision of information and expertise to assist the revision

of this volume, in particular:

Bedfordshire and Luton Fire & Rescue ServiceBuckinghamshire Fire & Rescue Service

Cheshire Fire BrigadeCornwall County Fire BrigadeDevon Fire and Rescue Service

GEC MarconiHertfordshire Fire & Rescue Service

Kent Fire BrigadeLondon Fire Brigade

Surrey Fire & Rescue ServiceWest Sussex Fire Brigade

Radio Frequency and Communications Planning Unit - Home OfficeASAP

BTBT Tallis Consultancy

Cable and WirelessCellnettFortek

Kingston CommunicationsMarconi

MultitoneOne 2 One

OrangeSimoco

Racal BRTC.S. Todd & Associates

TypetalkVodafone


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