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HUGHESNETWORK SYSTEMS LTD

A Hughes Electronics Company

Domestic L-Band Mobile Data Service

Interface Document

Satellite User Interface

for Telecomunicaciones De Mexico

Reference: A4-IFD-003076-5

Date: 11th January 2005

Issue: 3.7

Status: Accepted

Hughes Network Systems Limited Telephone +44 1908 221122Saxon Street Facsimile +44 1908 221127Milton Keynes MK14 6LDUnited Kingdom

Copyright Hughes Network Systems Ltd 2001

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A4-IFD-003076-5 Satellite User InterfaceIssue 3.7 - Accepted11th January 2005

The contents of this document are proprietary to HNS Limited and cannot be disclosed,duplicated, reproduced or used in part or in whole for any purpose other than in connec-tion with the associated binding contract between HNS Limited and the recipient. Thisrestriction does not apply to information in this document if it is obtainable from another

source without breach of this notice.

APPROVAL SIGNATURES

NAME : SIGNATURE :

JOBTITLE : DATE :

NAME : SIGNATURE :

JOBTITLE : DATE :

DISTRIBUTION LIST

Document Source: TCM TEAM: DOC, TCM LIBRARY: [IFD], TCM VERSION: SD_V3.7

To generate document: @IFD_SD

[ifd_sd.mss]

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REVISION HISTORY

Issue Status Date Author Change References

1.0A Draft 09-Sep-92 J.Barber Original

1.0B Pre QC 29-Sep-92 J.Barber Internal review comments

1.0 Accepted 25-Nov-92 J.Barber Following review

1.1A Pre QC 22-Dec-92 J.Barber New customer banners

1.1B Pre QC 31-Dec-92 J.Barber Further corrections, more banners

1.1C Pre QC 17-Feb-93 J.Barber SPR18905

2.0 Accepted 20-Aug-93 J.Barber SPRs 19414,19219. SCRs 22,130,133,211Updated to match Software Release 72000

2.1A Pre QC 01-Nov-93 J.Barber SPR 20499

2.1B Follow up 15-Nov-93 J.Barber Incorporate review comments

2.1 Accepted 23-Nov-93 J.Barber Final checks complete, for R72040

2.2A Pre QC 12-May-94 J.Barber SCR 287

2.3A Pre QC 01-Aug-94 J.Barber SCR 324,336. SPRs 21727,21810,21122

2.3B Pre QC 09-Aug-94 J.Barber Incorporate review comments

2.3C Follow up 16-Sep-94 J.Barber Further review comments, for R73000

2.3 Accepted 16-Sep-94 J.Barber Final checks made

2.4A For Review 29-Jan-95 M.Butcher SPR 20359,22091,22546,22615Specified Service codes,Format of Distress messages,Distress Alerts and Land Mobile Alerts

2.4 Accepted 21-Feb-95 M.Butcher After Review

2.5A For Review 06-Apr-95 M.Butcher Corrections to Distress formats andMinor clarifications to banners.

2.5 Approved 20-Apr-95 M.Butcher After Review + SPR23304

2.6A For Review 15-May-96 A. Chisholm ISOR and TMR5,SCRs 464, 481SPRs 24904, 24985

2.6 Accepted 1-Jul-96 A. Chisholm After Review

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REVISION HISTORY - continued

2.7A For Review 31-Jan-97 A. Chisholm FAX For Thailand.

2.7 Accepted 20-Feb-97 A. Chisholm After Review

3.0A For Review 1-May-95 M.Butcher Updated for Spot beam workingSCR61, for R80000

3.0 Accepted 10-May-95 M.Butcher Review comments included.

3.1A For Review 31-Oct-95 A Chisholm Updated delivery countdescr, SCR 298

3.1 Accepted 23-Nov-95 A Chisholm After Review

3.2A For Review 1-Aug-96 A. Chisholm Merge with V2.6

3.2B For Review 22-Oct-96 A. Chisholm AMR3, SCRs 505,507,512SPRs 25131,25147,25297

3.2 Accepted 1-Nov-96 A. Chisholm After Review

3.3A For Review 30-Jan-97 A. Chisholm GSOR, SCRs 414,531,549

3.3B For Review 6-Mar-97 A. Chisholm SCR 444

3.3 Accepted 7-Mar-97 A. Chisholm After Review

3.4A For Review 24-Apr-97 A. Chisholm IMR1, SCR555

3.4 Accepted 28-Apr-97 A. Chisholm After Review

3.5A Draft 08-Jun-1998 M.J.Williams Banner changes for SPR 24626 added

for Telstra and TI

3.5 Accepted 09-Nov-1999 M.J.Williams Note added for variable banner andDBE flag changes to banner description.

3.6A For Review 14-Feb-2001 M.J.Williams SPR 26330 Load balancing for Mexico

3.6 Accepted 26-Feb-2001 M.J.Williams Post review comments

3.7 Accepted 11-Jan-2005 M.J.Franklin CN: 137. Covert Security Alerts

Change bars highlight changes made since Issue V3.5 of this document

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Reporting Issues with this Document

Any errors or omissions found in this document should be reported to HNS by means of a

Customer Service Problem Report (CSPR). This method may also be used to raise any sugges-tions for future releases. The procedure for raising a CSPR is explained in Appendix F of theSystem Operator Console Operator Guide reference [2].

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Referenced and Related Documents

Reference:

1. Inmarsat-C SDM + CNs 92 - 98Identity: Issue: 1.3.1

2. Domestic L-Band data service Operator GuideIdentity: A4-OPG-003076 Issue: 3.6

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GLOSSARY

ABS Absent

ACK Acknowledgement

AORE Atlantic Ocean Region - East

AORW Atlantic Ocean Region - West

Call A connection originated by a user to enter messages or status requests intothe LES or a connection originated by the LES to pass messages or status toa user

CCITT International Consultative Committee for Telegraphy and Telephony

CNID Closed Network ID, identity of a network available to a group of registeredusers. Superseded by terms DNID and ENID

CU Channel Unit, the part of the LES and NCS configurations that provides the

communication path for a single satellite channel for an ocean regionData Report A short message sent on the signalling channel of the LES which may be

stored in a file associated with the DNID to which the report is sent

DNIC Data Network Identity Code. International code for identifying data networks

DNID The identity of a network available to a group of registered users. Used inprocessing data reports and messages sent in response to polls

EGC Enhanced Group Call - a broadcast message to one or more mobiles

ENID The identity of a broadcast network available to a group of registered users

Follow on messageThe ability to transmit more than one message in a single call setup

HNS Hughes Network SystemsIA5 International Alphabet Number 5. This is the default code for all Inmarsat-C

Mobiles

Inmarsat International Maritime Satellite Organisation - owners of various satellite sys-tems and regulators of the protocols for using those systems

Inmarsat-C Protocol defined by Inmarsat covering store and forward switching of mes-sages between terrestrial and satellite networks (previously referred to asStandard-C)

IOR Indian Ocean Region or Internal Ocean Region

ISL Interstation Signalling Link, used for communications between LES and NCS,

and also for communications between two NCSs. The LES has no ISL sinceno NCSs are involved

ITA2 International Telegraph Alphabet Number 2, a 5 bit code by Telex and also fortext compression over the satellite channel

LES Land Earth Station, the equipment providing the interconnection mobiles andterrestrial networks. Replaces the term CES

MES Mobile Earth Station. The terminal accessing the Inmarsat-C network via theInmarsat-C protocol. Replaces the term SES

Message Channel An inbound channel for transferring store and forward messages between anMES and the LES

Message Information destined for one or more addresses

Mobile Another term for MES

MRCC Maritime Rescue Communications Centre. Address for Maritime mobile dis-tress alerts and Maritime mobile distress messages

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NCS Network Coordination Station, coordinates the MESs and LESs in anInmarsat-C ocean region

NDN Non Delivery Notification

NMDD Non Maritime Distress Destination. Address for non-maritime alertsOcean Region One of: Atlantic (East), Atlantic (West), Pacific or Indian. Inmarsat-C satellites

operate over each of these regions

PDN Positive Delivery Notification

Poll A short message transmitted on the NCS TDM that can be send to one ormore mobiles as a broadcast message. A Poll can generate a response fromthe mobile in the form of a data report

POR Pacific Ocean Region

PSDN Packet Switched Data Network

PSTN Public Switched Telephony Network

PVT Performance Verification TestRoute A collection of paths to the next switching point

Rx Receive

SAC Special Access Code, a short code that is expanded by the LES into a fullterrestrial address. SACs can also cause the LES to perform a specificpredefined function

SD Satellite Driver (in LES terms this is the sub-system which provides the inter-face between the message handling subsystem and channel units).

SDM Inmarsat-C System Definition Manual

SIG Signalling Channel

Signalling ChannelA slotted aloha channel for sending signalling messages and data reports.Also known as an inbound channel

TDM Time Division Multiplexed communication channel from LES or NCS to aMES. Also known as the outbound channel

TDM Group Associated with a particular TDM output channel there are signalling and mes-sage channels. These channels are all associated in a TDM group

TNIC Telex Network Identification Code

Tx Transmit

Terrestrial User Usually a non mobile customer using the Inmarsat-C service, accessing theservice via Public Networks or Leased lines. Can also be a mobile user com-municating with another mobile via the terrestrial network

X.121 CCITT standard for DTE addressing format for destinations in the PSDN net-work

X.25 The international protocol for accessing a Public Switched Data Network

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Table of Contents

REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reporting Issues with this Document . . . . . . . . . . . . . . . . . . . . . . .

Referenced and Related Documents . . . . . . . . . . . . . . . . . . . . . . . .

GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.1. Domestic LES Operation . . . . . . . . . . . . . . . . . . . . . . . . . 2

2. TDM Bulletin Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33. Supported Presentation Codes . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1. Mobile to Shore Calls . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.2. Mobile to Mobile Calls . . . . . . . . . . . . . . . . . . . . . . . . . . 43.3. Shore to Mobile Calls . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.4. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4. Address Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65. Message Delivery Outcome . . . . . . . . . . . . . . . . . . . . . . . . . . . 76. Routing Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77. Distress Messages, Distress Alerts and Land Mobile Alerts . . . . . . . . . . . 88. Special Access Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89. Data Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910. Message text to mobiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 911. Follow-on Calls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

A. Call Completion Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

A.1. Message Confirmation and Message Status . . . . . . . . . . . . . . . . . . . A-1A.1.1. Non Delivery Notification (NDN) . . . . . . . . . . . . . . . . . . . . . A-1A.1.2. Positive Delivery Notification (PDN) . . . . . . . . . . . . . . . . . . . A-1A.1.3. Message Status Enquiry (MSE) . . . . . . . . . . . . . . . . . . . . . A-1

A.2. Call Completion Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

B. Distress Message, Distress Alert and Land Mobile Alert Formats . . . . . . . . B-1

B.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1B.2. Format of a Distress Message . . . . . . . . . . . . . . . . . . . . . . . . . . B-1B.3. Format of a Distress Alert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

B.4. Format of a Land Mobile Alert . . . . . . . . . . . . . . . . . . . . . . . . . . B-2B.5. Field Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3B.6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

B.6.1. Distress Message from Registered Maritime Mobile . . . . . . . . . . . B-4B.6.2. Distress Alert from Registered Maritime Mobile . . . . . . . . . . . . . B-5B.6.3. Distress Alert from Unregistered Maritime Mobile . . . . . . . . . . . . B-5B.6.4. Land Mobile Alert from Registered Mobile - Inmarsat Format . . . . . . B-6B.6.5. Land Mobile Alert from Registered Mobile - User Defined Format . . . . B-6B.6.6. Land Mobile Alert from Unregistered Mobile - Inmarsat Format . . . . . B-6

C. Reason Code Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

C.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

C.2. Reason Codes in Request Status Packets . . . . . . . . . . . . . . . . . . . . C-1

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List of Tables

1 Presentation Matrix for Mobile to Shore Calls . . . . . . . . . . . . . . . 4

2 Presentation Matrix for Mobile to Mobile Calls . . . . . . . . . . . . . . . 53 Presentation Matrix for Shore to Mobile Calls . . . . . . . . . . . . . . . 5A-1 Meaning of 2 or 3 character Call Completion Codes . . . . . . . . . . . . A-2A-2 Meaning of 2 or 3 character Call Completion Codes - Continued . . . . . A-3

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1

New Features

In V3.6 of the Satellite User Interface for MEXICO

This is the first Satellite User Interface Definition to be issued to MEXICO since V3.5. The majorchanges and improvements introduced since that issue are:

Section 1.1 has been updated to include description of Load balancing requirements.

The are also a number of minor changes and improvements which have been made as part of theongoing improvements to the customer deliverable documentation.

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2

1 Introduction

The purpose of this document is to define the satellite interface to the TELEMEX LES from thepoint of view of the MES user. However, as the satellite interface with the LES is defined in detail

in Reference [1] , there is no intention to duplicate that information in this document. Several fea-tures described in Reference [1] are optional. This document will state the options which are sup-ported by the LES, as well as provide information concerning the functions of the LES which arerelevant to the satellite user, but which are not covered in the Reference [1].

Unless otherwise stated, the LES fully supports all the mandatory protocols and servicesdescribed in Reference [1] .

Note: there are several differences in the way the LES operates, compared with what is en-visaged in Reference [1] ,

1. The LES operates permanently without an NCS, in Enhanced Standalone Mode.

2. The LES is primarily aimed at supporting non-maritime mobiles.

3. The mobile table must be set up manually by the LES operator.

1.1 Domestic LES Operation

The LES is designed to operate with a domestic, i.e. non Inmarsat-C, satellite. Mobiles thereforeneed to be pre-programmed to tune to the combined NCS/LES common channel(s) of the domes-tic network.

The LES ID of the Mexico LES (ie. 360) and the Primary TDM frequency needs to be programmedinto mobiles, the programming of which needs to be checked with the mobile manufacturer.

The mobiles must be programmed with the Primary TDM for each region that the mobile will becapable of operating within. The mobile will not need to have prior knowledge of any other TDMfrequency that is used by the LES within the region. If other TDMs are to be used the LES willsupply the frequencies in the relevant packet as part of the protocol.

It should be noted that the Station number which is contained in the lower 6 bits of the LES IDshould be constant for a given LES installation. The top 2 bits of the LES ID identify the part of theLES equipment that is transmitting the TDM to the region.

It is possible therefore that the Mobile may see more that one Primary TDM with the same stationnumber , this indicates that the LES is transmitting to more than one region, the mobile is at libertyto tune to and login into any Primary TDM that is visible and that has an LES ID containing one ofthe programmed station numbers.

The LES will attempt to load balance the mobile population across the available TDMs and mayuse the login protocol to force the mobile to tune to another NCS/LES common channel (the fre-quency is provided as part of the protocol) and log in again. If the mobile cannot log into the newfrequency and retries the login to the Primary TDM the second attempt will be accepted.

Since the domestic network is not intended for maritime mobiles, the mobile table of the LESshould only contain mobile numbers in the range 480000001 to 499999999 (i.e. the non-maritimerange). Mobile number 480000000 is reserved by the LES for the default non-maritime mobilenumber and should not be allocated to a real mobile.

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3

2 TDM Bulletin Board

The LES will broadcast a bulletin board every frame on its TDM(s), for each of the supportedocean region(s). The Bulletin Board gives the following information to the Mobile (see Reference

[1] for more details): Network Version - Always set to zero

Frame Descriptor

Frame Number

Number of Signalling Channels for this TDM

Number of 2-Frame Slots (by implication giving the number of 3-Frame slots)

Empty frame indication - indicates whether the Frame contains more than the

bulletin board and signalling channel descriptors.

TDM Descriptor

Channel Type

Joint Common and TDM

LES TDM Channel

Local ID - A sequence number to distinguish between multiple TDMs with thesame Origin ID

Origin ID - The LES ID including the Ocean Regionand Station number

Status

Return link speed - 300 or 600 BPS

Operational or Spare Satellite Indication

Services

Maritime Distress Alerting

SafetyNET Traffic

Inmarsat-C Traffic

Store and Forward

Half Duplex (Not Supported)

Full Duplex (Not Supported)

Closed Network

FleetNET Traffic

Prefixed Store and Forward Messages (Not supported)

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4

Land Mobile Alerting

Aero-C (Not supported)

Randomizing Interval - The number of frames that a mobile must randomize itsresponse after detecting collision during unreserved access to a signallingchannel

All supported services can be enabled or disabled by the LES operator.

3 Supported Presentation Codes

This section describes in tabular form the rules regarding handling of messages from/to MESs, forIA5, ITA2 and data presentation codes respectively, for the different destination networks sup-ported by the LES.

3.1 Mobile to Shore Calls

Table 1 relates to Mobile to Shore calls:

Destination Presentation Code Delivery Format andNetwork (received by the LES) Translation

Telex IA5 odd parity Translate to ITA2Telex ITA2 ITA2 (note 7)Telex Data Call rejected (note 1)

PSDN IA5 odd parity Call rejected (note 2)PSDN ITA2 Call rejected (note 2)PSDN Data Data

PSTN IA5 odd parity IA5 (note 3)PSTN ITA2 Call rejectedPSTN Data Call rejected (note 4)

DNID IA5 odd parity IA5DNID ITA2 Call rejected (note 6)DNID Data Data

Table 1. Presentation Matrix for Mobile to Shore Calls

3.2 Mobile to Mobile Calls

Table 2 lists the valid presentations for Mobile to Mobile calls:

3.3 Shore to Mobile Calls

Table 3 lists the valid presentations for shore to mobile calls:

3.4 Notes

This section provides additional information in note form on presentation handling and refers tonotes in Tables 1, 2 and 3:

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5

Destination Presentation Code Delivery Format andNetwork (received by the LES) Translation

Telex IA5 odd parity IA5 odd parityTelex ITA2 ITA2 (note 5)(note 7)Telex Data Call rejected (note 1)

PSDN IA5 odd parity Call rejected (note 2)PSDN ITA2 Call rejected (note 2)PSDN Data Data

PSTN IA5 odd parity Call rejectedPSTN ITA2 Call rejectedPSTN Data Call rejected

Table 2. Presentation Matrix for Mobile to Mobile Calls

Destination Presentation Code Delivery Format andNetwork (requested by user) Translation

Telex IA5 Translate to IA5 odd parityTelex ITA2 ITA2 (note 5)Telex Data Not allowed

PSDN IA5 IA5 odd parityPSDN ITA2 Translate to ITA2 (note 5)

PSDN Data As receivedexcept for special format characters

PSTN IA5 Not supportedPSTN ITA2 Not supportedPSTN Data Not supported

Table 3. Presentation Matrix for Shore to Mobile Calls

1. Mobile originated calls for the telex network whether to shore or to another mobilecannot be accepted if in data presentation as there is no U80 address line in themessage text which can be analysed.

2. Reference [1] requires that for messages to be delivered to a PSDN, the presen-tation field shall be set to the DATA code.

3. The acceptance of messages specifying PSTN destination network also requiresthat address extension field in the assignment request packet is correct as well asthe presentation code. The extension corresponds to a modem type.

Currently only T30 is supported. the message will be routed to G3FAX.

4. Acceptance of mobile to Shore calls to PSTN destinations in data format can beenabled by the LES administration. However, it must be noted that FAX converter atthe destination end will treat the text as IA5.

5. If the destination mobile terminal is marked as supporting ITA2, the message shallbe sent in ITA2 if the original message presentation is ITA2 (from mobile calls) orthe user requested presentation is ITA2 (from shore calls). For calls originating from

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6

unregistered telex, message delivery will be in ITA2 if the mobile is marked as sup-porting to ITA2.

6. Mobile originated messages to a DNID address are accepted if the presentation is

IA5 or data and will be passed transparently to the DNID file. Mobile originated mes-sages to a DNID address are rejected if the presentation is ITA2, since retrieval isnormally done using X25, which does not support ITA2.

7. Not applicable.

Other notes on presentation codes:

8. For mobile originated messages the destination network is that which appears in theassignment request packet. For shore originated messages the destination networkis the same as the network which originated the message to the LES and relates tothe way the mobile is addressed.

9. For mobile originated messages Presentation Codeis the code which is contained inthe assignment request packet. For shore originated messages Presentation Codeis the code the user requests for the message delivery.

10. For mobile originated messages destined to mobiles connected to other Inmarsatservices the considerations shown in Section 6 apply.

11. Where the destination from a message from a mobile is a Special Access code,which is associated with an address, the rules stated in Sections 3.1 and 3.2 for thedestination network corresponding to that address apply.

12. The X400 service is not supported by the LES. If an assignment request packet isreceived from the mobile specifying X400 as the destination network, the LES willsend a request status packet stating this service is not supported.

13. The CSDN service is not supported by the LES. If an assignment request packet isreceived from the mobile specifying CSDN as the destination network, the LES willsend a request status packet stating this service is not supported.

4 Address Validation

In addressing terrestrial subscriber(s) from a mobile, the full international address(es) must bespecified, up to a maximum permitted number. This number is 20 for Telex addressing, 8 for

PSDN and 7 for PSTN, the telex maximum being imposed by the LES and the PSDN and PSTNmaximum being implied in Reference [1] . The address(es) must include valid F69 (for telex),X121 (for PSDN) or E163/E165 (for PSTN) codes.

Addressing in asynchronous calls will have the destination network set to PSTN, and will be distin-guished by not being fax addressed (i.e. the address extension not being set to T30).

The LES will validate each address against the recognised CCITT codes. If the country code oraddress in the assignment request packet is found to be invalid, the LES will return a requeststatusreject packet, with the request status codeset to the appropriate value. Appendix C lists therequest status codes and their meaning.

After having accepted the assignment request packet as containing valid data, the LES checksthat all the addresses in the message packet are valid, e.g. F.69 code or DNIC is in the ap-propriate country code routing tables. If an address is found to be invalid, then the LES will returna forced clear packet to the mobile, containing a forced clear code. If the address validation is

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7

successful, then LES will attempt to deliver the message to all the valid addresses. Appendix Clists the forced clear codes and their meaning.

If, after having attempted to deliver the message, and when the delivery outcome for all addresses

is known, it is found not possible to deliver the message to one, some or all of the addressesspecified, a non-delivery notification will be returned to the originating mobile.

5 Message Delivery Outcome

Once the delivery outcome of a message originated from a mobile to shore or mobile to anothermobile is known, a positive delivery notification (PDN), if requested by the originator, or a non-delivery notification (NDN), if one or more deliveries failed, will be returned to the originatingmobile.

For NDNs, the message length, status (failure), number of attempts and address information isreturned together with a non-delivery code. The non-delivery code will be the CCITT defined ser-

vice code which corresponds most closely to the delivery failure. Each failure reason has an as-sociated pre-determined number of attempts to deliver the message before the LES fails thedelivery. The number of attempts and delay between attempts is defined by the LES operator foreach failure reason.

Appendix A gives further details of the Confirmation and Message Status information returned bythe LES and the Table A-1 defines the set of service codes which can be returned for unsuc-cessful deliveries, and these will be included in any NDN, PDN or Message Status that isgenerated.

The mechanism for sending message delivery confirmations is shown in Reference [1] . The LESwill send details which relate to each delivery address, and will use however many packets are

needed to convey all the information. A similar mechanism applies for message status enquiries.On receipt of a request, the LES will return the current status for all deliveries associated with themessage being enquired on. The same set of service codes as for delivery confirmations will beused.

6 Routing Considerations

Providing the destination address(es) have been correctly specified, and the destination network isone which is supported, the LES will undertake, as far as possible, to deliver the message to allthe required destinations.

In the case of terrestrial to mobile or mobile to mobile calls the, LES will attempt to deliver onlywhen the destination mobiles are logged into a supported ocean region. However, where theTelex destination network is specified in the assignment request packet, and the mobile beingaddressed is declared as in an ocean region not supported by the LES, the message will berouted via the international Telex network, unless inhibited by the LES routing tables. The non-supported ocean regions and destination networks which can be addressed are ultimately underthe control of the LES operator.

If the mobile being addressed is Inmarsat-A or Inmarsat-B, messages will be routed via the ap-propriate terrestrial network, provided the LES routing tables permit it.

Mobile addresses in mobile to mobile calls will be preceded by 111, if PSDN is specified forthe destination network, and 58 if Telex is specified for the destination network, where isthe Inmarsat-C ocean region (1 = AORE, 2 = POR, 3 = IOR, 4 = AORW). However, routingdirectly via the LES will only take place if is 0, since values 1 to 4 will be considered asInmarsat-C ocean regions. These could be accessed by other LESs, via the appropriate terrestrialnetwork, but only if the LES routing tables are set up to permit it. The default values are that if

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8

is not equal to 0, the message is rejected.

It is possible to route messages via the PSTN network, to terminals with CCITT V-series modems.The LES will treat all messages addressed to the PSDN network, whose first address digit is 9,

as needing to be routed via the PSTN network. The expectation is that at the destination there willbe a terminal, connected via a suitable modem, which supports an Asynchronous interface withthe LES. In order for message to be accepted by the LES, all addresses must follow with a validE163 or E165 code and then the national number (totalling no more than 13 digits).

It is possible to route messages via the PSTN network, to Group 3 Fax terminals. In order tosuccessfully route the messages, the destination address must be known in the LES routingtables, and the assignment request packet must specify routing via the PSTN network with ad-dress extension T30.

7 Distress Messages, Distress Alerts and Land Mobile Alerts

For originating mobiles whose numbers begin with 40 to 47, the LES routes Distress Alerts, andmessages at distress priority, to the MRCC position. Distress Alerts from unregistered mobiles willalso be routed to the MRCC position. Distress Alerts and messages at distress priority will berouted by the LES at distress priority. If a Land Alert is received from a 40 to 47 mobile, strictlyan illegal condition according to the protocols of Reference [1] this too will be routed to the MRCCposition, but at normal priority.

For originating mobiles whose numbers begin with 48 or 49, the LES routes Land Alerts to to anaddress set up by the LES operator associated with that particular mobile, or if no address is setup, to a default NMDD position. Land Alerts from unregistered mobiles will also be routed to thedefault NMDD position. Land Alerts will be routed by the LES at normal priority. If a Distress Alertor message at distress priority is received from a 48 or 49 mobile, strictly an illegal condition

according to the protocols of Reference [1] this too will be routed to the specified NMDD position,but at distress priority.

The satellite interface of the LES is responsible for formatting the distress alert or land alert pack-ets. This ensures that the content of an alert will have the same format irrespective of the interfacefrom which it is delivered.

The options for delivery or retrieval of the formatted alerts are:

Telex Delivery

Fax Delivery

X25 Delivery

Operator Console

Distress Report

The specification of the format used is contained in appendix B. The header or banner and anyend of message indication will be specific for the report or delivery driver used.

8 Special Access Codes

Special Access codes are 2-6 alphanumeric characters which generally translate to an address forone of the supported destination networks. These will be set up by the LES operator. Only thosecodes previously set up will be accepted by the LES. The LES operator may select one or more

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9

codes to translate to the service whereby the message is sent to the operator. SAC 33 is oftenchosen for this purpose.

9 Data ReportingThe LES supports the unreserved data reporting services but not the reserved (pre-assigned) datareporting services.

10 Message text to mobiles

The message text received by the LES will be the same as that sent to the mobile, but note thefollowing:

1. If a message text from a terrestrial telex subscriber is received but is not properlyterminated e.g. allowed to time out, the following text shall be appended: THISMESSAGE MAY BE INCOMPLETE.

2. If message text has to be translated from ITA2 to IA5 then the following translationsapply:

Null translates to Null

Figure Shift F translates to %

Figure Shift G translates to

Figure Shift H translates to #

All other ITA2 characters shall be translated to the IA5 equivalent

3. Messages sent to mobiles in ITA2 code will be packed into successive bytes asdefined in Reference [1] . If message text has to be translated from IA5 to ITA2 thenthe following translations apply:

Null translates to Null

* translates to Figure Shift C (:)

: translates to Figure Shift C (:)

% translates to Figure Shift F

@ translates to Figure Shift G

$ translates to Figure Shift H

All other IA5 characters shall be translated to the ITA2 equivalent, exceptwhen there is no equivalent, in which case the character shall be translated to?

11 Follow-on Calls

In order to make most efficient use of satellite bandwidth the LES, when delivering to a mobile, willsend up to ten messages in one call session. The LES imposes a limit of ten in order that onemobile does not monopolize use of satellite bandwidth. For calls originating from the mobile onlyone message can be sent in one call session, in accordance with the protocols of Reference [1] .

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A-1

Appendix A

Call Completion Codes

A.1 Message Confirmation and Message Status

The LES signals the state of a message transfer to a mobile using either the confirmation packetor the message status packet. These packet formats are identical, however the usage is different.

These packets will contain the address and status for all the destinations requested in the order inwhich the mobile originally specified them. This enables software at the MES to easily tie up therequested destination and the status.

A.1.1 Non Delivery Notification (NDN)

The LES will always send a confirmation packet to a mobile if a call to any of the destinationaddresses specified for that message does not result in a success (SUC) status. This happenswhen the delivery cycle (ie. all reattempts) to all destinations has completed. This use of theconfirmation packet is equivalent to a Non Delivery Notification.

A.1.2 Positive Delivery Notification (PDN)

If the mobile requested confirmation in the announcement packet for the message the LES willsend a confirmation packet to a mobile irrespective of the final outcome of the delivery cycle to alldestinations. This use of the confirmation packet is equivalent to a Positive Delivery Notification.

A.1.3 Message Status Enquiry (MSE)A mobile may request the status of a message using the Message Status Request packet. TheLES will send the message status packet in response if the request comes from the mobile thatsubmitted the message and the message status information is still held at the LES (this is typicallyheld for 72 hours from the time of the message submission).

The status for each destination will be the latest known by the LES and may differ from the finalstatus.

The FAX delivery attempt count remains at zero until all delivery attempts have been completed.

A.2 Call Completion CodesThe meaning of the two or three character codes returned in the confirmation and message statuspackets is given in Table A-1. These are the factory settings; different codes may be defined bythe LES administration.

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A-2

CCC Meaning Description

ABS Absent Subscriber The MES is not logged in or thenumber called is not obtainable

BK Clear Down The call was cleared down by eitherCancelled the LES, the called party or theMessage Aborted destination network.

BMC Premature end of message The message was received incomplete

DBU Unconfirmed Delivery cannot be confirmed

DER Out of Order An error has been detected in theprocessing of the message caused byequipment failure or failure to

follow protocol.

DTE Remote DTE Cleared The remote user or equipment clearedthe call.

FMT Format Error The address format, presentation codeor message format was incorrect.

IAB Invalid answerback The answerback of the called telexsubscriber did not match theanswerback specified.

INF Call the Network Call the information service relevantInformation Service to the destination network that was

addressed.

INV Invalid Call The call was invalid

ITD Awaiting Delivery The call is awaiting delivery or isin progress or has been placed witha third party store and forward system

JFE Telex Closed The Telex network is not available

LDE Maximum Message Length The message was too long for theExceeded protocol to handle.

LPE Local Protocol Error The message could not be processedie. a presentation code conversionerror occurred.

MOM Waiting The destination is waitingie. a Mobile waiting for clear.

Table A-1. Meaning of 2 or 3 character Call Completion Codes

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A-3

CCC Meaning Description

NA Access Barred Access to the number or serviceis not possible.

ie. MES barredor MES not commissionedor Invalid Addressor Service not providedor Invalid Presentation Code

NC Network Congestion The call has failed due to a lackor of resources or there is no path toNo Circuits the destination.

NCH Subscribers Number The destination is no longer valid.Has Changed

NDA No Delivery Attempt Has No attempt has been made to deliverhas been made the message.

NP Not Permitted The destination is in the correctformat but cannot be accessed.ie. Number not Obtainableor Mobile not Registered

NRC Reverse charging Accept The destination would not accept theNot Subscribed call.

OCC Occupied The destination number was busyThis will be signalled after allretries have been completed.

RDI Redirected Call The call was redirected

RPE Remote Protocol Error The remote equipment signalled aprotocol error.

RTD Incoming Retest Detected The outgoing telex call detected

that the line was in retest.

SUC Success The call succeeded.

TMD Too Many Destinations Maximum Number of AddressesExceeded

UNK Unknown The current or final outcome of acall is unknown.

Table A-2. Meaning of 2 or 3 character Call Completion Codes - Continued

[ifd_sd_ccc.stx]

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B-1

Appendix B

Distress Message, Distress Alert and Land Mobile Alert Formats

B.1 Introduction

The following gives a definition of the formatting applied to Distress messages, Distress Alerts andLand Mobile Alerts. All characters output are plain text such that the output will be identical in ITA2or IA5 alphabet apart from the case.

The characters are used to indicate that the field is variable and will contain an indication of thenumber of digits or a field name. For example will indicate a 2 digit decimal field with leadingzeros suppressed (see the Note below), is a two Hex character field and will indicate that the field will take one of the possible values of the vari-able string Distress_Protocol_Str.

The fields are defined in section B.5 in alphabetical order. apart from which is the spacecharacter, and which is the character pair, carriage return and line feed.

The format of the definitions are

:= "" |"" |""

Where the | character indicates OR.

Note that decimal fields have leading zeros suppressed apart from the time string (HHMM) and

the land mobile latitude and longitude seconds field as indicated in the formal definitions of theformats below.

Note also that text strings include the trailing spaces as specified and are not trimmed.

B.2 Format of a Distress Message

A distress message received from a mobile will have the following general form

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B-2

B.3 Format of a Distress Alert

A distress alert received from a mobile will have the following general form

DISTRESS ALERT FROM MOBILEMobile Number :Ocean Region :LES ID :()Latitude (Degs Mins) :Longitude (Degs Mins) :Position Updated At (HHMM) :Protocol :Distress Type :Speed :

Course :Was Position Updated In The Last 24 Hrs :Was Course/Speed Updated In The Last 24 Hrs :Was Alert Auto Activated :

(Note: the units of SPEED are Knots and COURSE is degrees from True North)

B.4 Format of a Land Mobile Alert

A land mobile alert received from a mobile will have the following general form

LAND MOBILE ALERT FROM MOBILEMobile Number :Ocean Region :LES ID :()Latitude (Degs Mins Secs) :.Longitude (Degs Mins Secs) :.Manual Position Entered :Protocol :

Land Alert Format :

If = "Inmarsat Format " then the remainder of the Land Alert will be :-

Nature of Land Alert :Was Alert Auto Activated :Time of Position :Speed :Direction of Travel :Extra Information (Hex) :

If = "User Defined " then the remainder of the Land Alert will be :-

User Defined Field 1 (5 bits) :User Defined Field 2 (8 bits) :User Defined Field 3 (8 bits) :

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B-4

Lat_Str := "North" |"South"

LES_ID_Str := ie. "360"

LES_Region_Str := "IOR"

Long_Str := "East" |"West"

Maritime_Mobile_Number := "40" |"41" |

"42" |"43" |"44" |"45" |"46" |"47" |"400000000"

Protocol_Str := "Maritime " |"Land Mobile" |"Reserved "

Return_ID := ""

Return_ID_Str := "Return ID :" |""

Note: The return ID is only given in the case of an alert from an unregisteredmobile. An unregistered mobile cannot successfully send a distress message.

Station_Str := ie. "TELEMEX"

Note: The name used is as the station name in the LES database.

[ifd_sd_distress_strings.stx]

B.6 Examples

B.6.1 Distress Message from Registered Maritime Mobile

Example:ASSISTANCE REQUIRED, SHIP HAS GONE AGROUND.

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B-5

B.6.2 Distress Alert from Registered Maritime Mobile

Example:

DISTRESS ALERT FROM REGISTERED MOBILE

Mobile Number : 412345678Ocean Region : IORLES ID : TELEMEX (360)Latitude (Degs Mins) : 39 51 SouthLongitude (Degs Mins) : 87 29 EastPosition Updated At (HHMM) : 1446Protocol : MaritimeDistress Type : UndesignatedSpeed : 0Course : 0Was Position Updated In The Last 24 Hrs : NOWas Course/Speed Updated In The Last 24 Hrs : NOWas Alert Auto Activated : NO

B.6.3 Distress Alert from Unregistered Maritime Mobile

Example:

DISTRESS ALERT FROM UNREGISTERED MOBILE

Mobile Number : 400000000Return ID : 3116022Ocean Region : IORLES ID : TELEMEX (360)

Latitude (Degs Mins) : 39 51 SouthLongitude (Degs Mins) : 87 29 EastPosition Updated At (HHMM) : 1446Protocol : MaritimeDistress Type : UndesignatedSpeed : 0Course : 0Was Position Updated In The Last 24 Hrs : NOWas Course/Speed Updated In The Last 24 Hrs : NOWas Alert Auto Activated : NO

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B-6

B.6.4 Land Mobile Alert from Registered Mobile - Inmarsat Format

Example:

LAND MOBILE ALERT FROM REGISTERED MOBILE

Mobile Number : 481234567Ocean Region : IORLES ID : TELEMEX (360)Latitude (Degs Mins Secs) : 50 0 0.0 NorthLongitude (Degs Mins Secs) : 1 0 0.0 WestManual Position Entered : FalseProtocol : Land MobileLand Alert Format : Inmarsat FormatNature of Land Alert : Severe WeatherWas Alert Auto Activated : YESTime of Position : 1 to < 5 minutes oldSpeed : Fast > 70 km/hDirection of Travel : EastExtra Information (Hex) : AB

B.6.5 Land Mobile Alert from Registered Mobile - User Defined Format

Example:

LAND MOBILE ALERT FROM REGISTERED MOBILE

Mobile Number : 481234567Ocean Region : IORLES ID : TELEMEX (360)

Latitude (Degs Mins Secs) : 50 0 0.0 NorthLongitude (Degs Mins Secs) : 1 0 0.0 WestManual Position Entered : FalseProtocol : Land MobileLand Alert Format : User DefinedUser Defined Field 1 (5 bits) : 1FUser Defined Field 2 (8 bits) : A5User Defined Field 3 (8 bits) : 00

B.6.6 Land Mobile Alert from Unregistered Mobile - Inmarsat Format

Example:

LAND MOBILE ALERT FROM UNREGISTERED MOBILE

Mobile Number : 400000000Return ID : 3116022Ocean Region : IORLES ID : TELEMEX (360)Latitude (Degs Mins Secs) : 50 0 0.0 NorthLongitude (Degs Mins Secs) : 1 0 0.0 WestManual Position Entered : TrueProtocol : Land MobileLand Alert Format : Inmarsat FormatNature of Land Alert : Severe WeatherWas Alert Auto Activated : YES

Time of Position : 1 to < 5 minutes oldSpeed : Fast > 70 km/hDirection of Travel : EastExtra Information (Hex) : AB

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B-7

[ifd_sd_distress_formats.stx]

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C-1

Appendix C

Reason Code Definitions

C.1 Introduction

Reason codes are raised if address validation of terrestrial users is unsuccessful. The reasoncode will be returned by the LES. The packet raised containing a reason code will depend uponwhich stage of address validation an invalid entry is detected.

C.2 Reason Codes in Request Status Packets

Request Status Code Meaning

01H LES message store full

02H Requested destination not served03H Satellite congestion04H Terrestrial congestion05H Requested service not provided06H Request in queue07H Request barred08H MES not logged in09H MES not commissioned0AH Waiting TDM assignment0BH Illegal request0CH LES not in service0DH Requested service temporarily unavailable

0EH Access to requested service denied0FH Invalid service10H Invalid address (in assignment request)11H-14H Spare15H PSTN modem type not supported16H-7FH Spare

C.3 Reason Codes in Forced Clear Packets

Forced Clear Code Meaning

01H LES timeout

02H MES protocol error detected03H LES fatal hardware error detected04H Operator forced clear05H MES forced clear06H LES protocol error detected07H MES hardware error detected08H MES timeout09H Unrecognized presentation code0AH-0CH Spare0DH Requested service temporarily unavailable0EH Access to requested service denied0FH Invalid service

10H Invalid address11H Destination MES not commissioned12H Destination MES not logged in13H Destination MES barred

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14H Requested service not provided15H-FFH Spare