67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · brief history ofcordless phones...
TRANSCRIPT
![Page 1: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/1.jpg)
![Page 2: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/2.jpg)
![Page 3: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/3.jpg)
![Page 4: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/4.jpg)
![Page 5: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/5.jpg)
![Page 6: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/6.jpg)
![Page 7: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/7.jpg)
![Page 8: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/8.jpg)
The Elegant Instrument
The telephone instrument is one of themost elegant, and carefully designed
of all electron ic devices on Earth.
They ere also one 0' the Easiest andr-iost Commor. -:-hings To Turn Into
Bugs or Eavesdropping Devices
![Page 9: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/9.jpg)
![Page 10: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/10.jpg)
![Page 11: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/11.jpg)
![Page 12: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/12.jpg)
•••
•-.•
• •-0 --.
n ." ~ ..,-•• •--. _• • •
,
![Page 13: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/13.jpg)
![Page 14: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/14.jpg)
Telephone Vulnerability Points
1. Cordless Phones Provide MoreAttack Surface then a HardwiredPhone
2. Many People are Totally CluelessAbout the Risk of Cordless Phones
3. How Many Cordless Phones Do YouHave In Your Life?
![Page 15: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/15.jpg)
Brief History of Cordless Phones
• Invented by George Sweigert• World War II Radio Operator
• Injured During War
• Radio Controlled Telephone Coupler• Submitted Patent : May 2, 1966, us 3,449,750
• Invented Full Duplex Radio Operation• Full Remote Control of Phone
• Used a Relay To Activate and Release Phone• Parts From A Washing Machine
• Acoustic Coupling, Not Direct Connection• Direct Coupl ing Into li ne Came Later
![Page 16: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/16.jpg)
Brief History of Cordless Phones
1969 Initial Cordless Phones Sold
1972 WECO Markets Cordless Phone
1980 Sony Cordless Phone Chip Sets
1984 AT&T/WECO Break Up
1984+ Cordless Phones Gain Popularity
![Page 17: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/17.jpg)
![Page 18: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/18.jpg)
![Page 19: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/19.jpg)
FCC Definition
• 47 CFR § 15.3 DefinitionsU> Cordless telephone system
• A system consisting of two tra nsceivers, one a basestatiQn t hat connects to the public switched telephonenetwork and t he other a .m..o..b.i.l.e.andset unit thatcommunicates directly with the base station .
• Transmissions from the mobile unit are received by thebase station and then placed on the publ ic switchedtelephone network . Informat ion received from theswitched telephone network is t ransmitted by t he basesta tion t o the mob ile unit.
![Page 20: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/20.jpg)
![Page 21: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/21.jpg)
![Page 22: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/22.jpg)
![Page 23: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/23.jpg)
![Page 24: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/24.jpg)
![Page 25: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/25.jpg)
![Page 26: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/26.jpg)
![Page 27: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/27.jpg)
Cordless Phone Eavesdropping
• Eavesdropper Complain:• Not Fair, that They Got Ca ught
• The Spy Hunter Measured:• Scanner from 900 feet away• Scanner Listening to Neighbors Cordless Calls• Victim 75 feet Away from Eavesdropper• Spy Hunter Measuring, But Not Eavesdropping
Spy vs. Spy vs. Spy
![Page 28: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/28.jpg)
![Page 29: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/29.jpg)
Auditing Telephone Instruments
• What Kind of Phones• "Soft Under-Belly "• What Should It Normally Do
• Is It a Risk?
• Is It a Threat?• Hostile Manipulation ?
Featur-e, [-[azard, or Risr<?
![Page 30: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/30.jpg)
![Page 31: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/31.jpg)
Cordless Phone Frequencies
Seven (7) Officially Allocated USA Bands• 1.7 MHz (allocated pre- 1976)• 27 MHz (allocated in 1980)• -1::; - 30 '.' Hz (allocated in 1986)• S02-928 ~",Hz (allocated in 1990 )
• 1880- 1900 MHz (DECT, non-US usage)• 1920 1930 r>lHz (DECT, allocated 200 5)
• 2,-l GHz (a llocated in 1998 )
• 5,8 GHz (allocated in 2003)
![Page 32: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/32.jpg)
Cordless Phone Frequencies
1.7 MHz Band• 1974 - 19 86 era
• Heavy Ferrite Bar Antenna• Huge Battery. Short Life• AM Modulated• Massive Interference• Often Illegal Power Levels• Banned by Phone Company• Unless you rented a WECO unit from them• Very Congested Spectrum Area• Phased Out in 1984• Your Parents Cordless Phone ·:or 9r~n<l P<'rcnt~)
![Page 33: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/33.jpg)
Cordless Phone Frequencies
27 MHz Band• 1980 - 1986 era
• Basically a Two Channel CB Rad io• Long Telescoping Antenna• Huge Battery, Little Life• AM Modulated• Massive Interference• Often Illega l,S wa tt +• Very Congested Spectrum Area• Often Paired with 1.7 MHz• Huge $$$ Long Distance Bills• Phased Out in 1984• Your Parents Cord less Phone (or9 r~n<lp~rcnt~J
![Page 34: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/34.jpg)
Cordless Phone Frequencies
43 -50 MHz Channels'-----""----', H >10 03 1601 Hl~ 08._J . ) .RO <8.860• H8CI 08 ~.lG
S OJ 910 '9 020~ oJ 960 49 01101 "'.1.10 49 . ' 008 ... 1110 491609 "'uo 49 10010 " .100 . 9 140II " . l 10 .9,180II J.W . 9 360I ) 00 49.400,. • • .• W 49 ,4,;015 • •. • 60 49.50016 46 .6 10 49 ,610" 46 .6 30 '9 ,8' S18 46 .6 7(1 49 960I ~ '6 '10 49 71010 46 no 49 9 ' S), 46710 ' 9 8 )0)} .~ 830 49890), '6 810 '99JO}. 46 930 4.990}\ 4(, 9'0 49910
• 1984 to Present
• Often Large Antenna
• Very CongestedSpectrum Area
• Being Phased out inFavor of 900 MH zBand
![Page 35: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/35.jpg)
Cordless Phone Frequencies
902-928 MHz ISM Band• 1990 - Present Era
• Short Antenna , 6-8"• Spectrum Congested• Ext remely Cheap NFM Modulat ion• Single Chi p Solutions• Decent Dista nces• Usua ll y FM Modulat ion• Poor Choice for Dig ita l Modulat ion• Sometimes FHSS or 0555• Originall y $400 - $500 for a 900 MHz Phone• Did Not Become Cost Effective Unti l Prices Dropped• < $150 per System was the Break ing Point• Now < $20 per system
![Page 36: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/36.jpg)
Cordless Phone Frequencies
DECT - Digital Enhanced Cordless Telecommunications
• 2005(u-s.) - Present Era• 1880-1900 MHz (DECT, non-US usage)• 1920 -1930 MHz (DECT, allocated 2005)
• Internal Antenna• Only 10 MHz of Spectrum Allocated in U.S.• Congested, but Dig ital Signal Opt imizes Spectrum
• GFSK Modulation ( 1. 152 Mbit/Sec)• International Standard• Very Cheap Due to Huge Qua nt it ies Being Made• Extended Range, 1000+ ft common• Long Battery Li fe
![Page 37: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/37.jpg)
Cordless Phone Frequencies
2.4 GHz ISM Band• 1998 - Present
. 2.4- 2.483 GHz• Usually Internal Antenna• Congested Band• Cheap, Consumer Grade• Good Choice for Digital Modulation• Digita l and Analog Hybrid s or SS• Could be FM Modu lated• Cou ld be paired with 900 MHz. 802.11 I nterference Issues
• Becom ing Less Popular Due to WLAN and BT Issues
![Page 38: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/38.jpg)
Cordless Phone Frequencies
5.8 GHz ISM Band• 2003 - Present
• 5.725 - 5.850 GHz• Internal Antenna• Uncongested Band (for now)• Cheap, Consumer Grade• Extremely Bad Signal Propagation• Dig ita l and Analog Hybr ids or SS• Digita l Modulat ion is Pr icey• Could Be, Often Is FM Modulated• Could be pa ired with 2.4 GHz• 802 .11 Inte rfere nce Issues
![Page 39: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/39.jpg)
Cordless Phone Frequencies
European and Asian Cord less Phones• Illegal to sell or use in the US• Not FCC Approved• Frequency Ranges
• 864.1 - 868 .1 MHz• 885 - 887 MHz• 930 - 932 MHz• 959 - 960 MHz
• Similar is size, function, feat ures, cost,and appearance as legal 900 MHz Units
![Page 40: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/40.jpg)
Cordless Phone Frequencies
Asian PHS " Handy Phones"• Illegal to sell or use in the US• Not FCC Approved• Frequency Range
. 1895 - 1906.1 MHz
• Third Generation Cord less Phone• Similar Operat ion as Cell Phones
![Page 41: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/41.jpg)
Cordless Phone Frequencies
Japanese 254/380 MHz Phones• Illegal to sell or use in the US• Not FCC Approved• Frequency Ranges
• 253.85 - 255 MHz
• 380.2 - 381.325 MHz
• Paired Frequencies• US Mil itary Hunts Abusers
![Page 42: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/42.jpg)
![Page 43: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/43.jpg)
Cordless Phone Modulation
• Narrow Band Frequency Modulation. 43-50 MHz
. 900 MHz
. 2.4 GHz• 5.8 GHz
• Extremely Cheap to Do
• I neffective Use of Spectrum
• Huge Amount of Wasted Bandwidth
![Page 44: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/44.jpg)
![Page 45: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/45.jpg)
Cordless Phone Modulation
• Spread Spectrum• Needs Bandwidth
• Frequency Hopp ing• Direct Sequence
• Signal In The Noise (Pseudo Noise Actually)• Very Efficient Use of Spectrum• Code Domain Modulation
• Shared Channels• Low Level Privacy
![Page 46: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/46.jpg)
![Page 47: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/47.jpg)
Attack Surface
Digital Control " Feat ures"• I ntercom• Paging• Three Way Calling• Listen -In• Barge-In
• Base or Remotes Can Seize Control
![Page 48: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/48.jpg)
FCC Security Requirements4 1 ,n , 'J.' " ,.....In. 'elepho_. Ig!e-...........,..._~..~<>«u _ ........... do9'<..~<O*to_..."""",","'" ..,,""' .....n._...<....l tu ,..I>.'; _""",_ by _
"",...oont_ P<olIi~ ""~-i..- '-ct..........-. oct> O«<'H <II ,_....WO'!< ' 0', ......_ .. ..-..:_ I>r ".........- ~~-.... to '''''- ",,"' <><NO' ""'" ~ <OH _ "" .... ,_.....m.- ....... ."....--,""-,,, __ ...... __ "'"' cCCUO' ..... , .... <0<10 -... "" ........ _ "'OtC'>OO "'" _ ......--_~__"' ""''''''_M_'''~_~''_''-'-<,
r...::.,~-"bo -·"'l-"'" ~....,......._ ...........to_."'~ ....fl1 ...·.... "' ..... ,,............ '..-..__ ,"*,_", ,_ ............'''- ..~ r;o........., ,-. "" , ',.,<V>o<'><" ......."',""" ...... c-. __ ............_ •__~--...-.... ",....,~ ,.,.,. -,» - ~.. -~...,...", "" -"', ~ -_..... ..,. •••.,........... .,.. " .....-- .........."'" "
.~ • .wo' "".". ,,,,.">( I .."..........._ '0< '0 ' , """'"' """ -.,.." .. ..- 1'>6 OOS'-bi<- _ -..""'" .,.."~ ,". """-<>0<'<_ "'>d< ""'... "' """ ,.....
......~. """ ,_ cr ""' -"~ """ , ......."""'" ' ..... "' ""'"My ,_ ..• oct> __ '" on><Iu<<<I•'l i>rq><.".. • ~.«I cod< nCO.""""""" '00'''' """"'i ....... 1% co"''''. <>9>'" ,_ .. _,'....0...,..," 'act ....(.,: """',.,.. ","" 'o<d.... ,..~". '0 'L''''''''",O'''' """" a 0._ '_""'" ''''''"Q''
...... 1~6 ..",_ o".,,~. 0'."" ,__" ~...... , • 0<:1""""( _j " .. ,.,,,.,'...... to 0'0 (0,,"' .......... of _''''''• ....,.,..,..", ond """ "'1«<.... ''''''''Q 0'0..,..,
' ''''''0 ""0""."' ......( l: • ".k "' d "'" ""''''' ..-<1 ..",<",-"", c""'" " ~ , .••• ,.... '''O'' ,,'" ,""",.,.... , ...', "" "C"''''' ";0', "",,,," '"'w o"~",_,'01 "'-''''' ,," "" 0' • ""~.." "<"' ''''.
N ". r,..,· ,,' e"" ""'to. """,
What does all of this really mean?
![Page 49: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/49.jpg)
FCC Security Requirements
47 CFR § 15.214 Cordless Telephones
3DLDJ11 Li:1e:1) Zero Privacy2) Minimal 8-bit Security3) Controls~ Access4) Illusions of Privacy
5) It is a Door Knob, Not a Lock
![Page 50: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/50.jpg)
Access Security
• Small Number of Access Codes• As few as 8-bits, could be hundreds• Not Actual Security
• Just Minor Traffic Control• Keeps the Neighbors Off "Your Line"• Is Not Encryption
![Page 51: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/51.jpg)
![Page 52: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/52.jpg)
Transmission Security
• Not Practical on Consumer Devices• Requires Expensive Parts• Signal Bandwidth Issues
• Digi ta l Modulat ion Provides Lim ited, butnot Good Privacy
• Even Spread Spectrum and FrequencyHopping is not Private• The hopping codes, algorithms, and patterns
are widely known and openly publ ished
![Page 53: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/53.jpg)
Interception Basics
• Base Station is Usuall y More Powerful t henMobile (just like with cell phones)
• Upli nk and Downl ink May or May Not EvenBe Withi n Same Band• Remote = 910.5 MHz• Base = 24 19 .75 MH z
• Often Cheaper to Stay Within Band• Remote = 904 MHz• Base = 9 18 MH z
![Page 54: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/54.jpg)
Interception Basics
• Two Cheap $50 RadioShack Scanners• Handset Dedicated• Base Dedicated
43-50 MHz Channels~I 41 '10 q '0;0l 41 7«1 q .S40) 'J tlO q ._• t J _ .. 919~ 41 910 49 010• 4)_ 49 010, .. no 49.11108 .. 161) '9 1609 .. I to) 09 100'0 .. 10(1 09 lOGII " . )J(l O'j.l llO12 .. )6(l 09 l60II "'00 <9000.. ........ <9 . 60IS "'eo '9~16 6'0 49 6 ' 0" 6)0 49 8<0 ';I. 6]0 4981\019 4. 710 49 no10 46 710 498 "1: 0. 110 498JOn 46 8 10 49890II '" 8 10 <99 JO1< .. 9W 49 'f9O1\ 46 9 10 49 9 '0
•
•
25 Channels Each
Radio Shack Pro-82• 200 Channel• PN 20-3 15• 29-54 MHz
![Page 55: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/55.jpg)
![Page 56: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/56.jpg)
![Page 57: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/57.jpg)
Interception Basics
Rad io Shack or Wa l-Mart Scanners• <$1 50 Total Investment• Intercept and Demodulate at 900 MHz• 100 Feet Away (Maybe), Rubber Ducky. 300+ Feet, Extern al Antenna
![Page 58: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/58.jpg)
Interception Basics
Mid Range Scanners• <$600 Total Investment• Intercept and Demodulate at 900 MHz. 200-500 Feet Away, Rubber Ducky• 1000+ Feet, External Antenna
![Page 59: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/59.jpg)
Interception Basics
High End Receivers• > $2400 Total Investment• Intercept and Demodulate at 900 MHz· 300- 1200 Feet Away, Rubber Ducky. 3000+ Feet, External Antenna• Antenna is High Mounted on Mast
![Page 60: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/60.jpg)
![Page 61: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/61.jpg)
Analog Cordless Phones
• Virtual Zero Security• Usually Zero Encryption• Narrow FM Modulated Signal
• Tough Not to Trip Over Signal• Two Signals on Spectrum
![Page 62: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/62.jpg)
![Page 63: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/63.jpg)
Intercepting Analog
• Identify Band " Edges"• Program into Scanner in Seek Mode
• i.e. : 902 - 928 MHz
• Set Steps to <V4 Expected Signal BW• 2.5 kHz for a 10 kHz BW• Smaller is better, but slower
• Adjust for Best Audio• Use AFC and AGC
• Find the "Ot her Half" of Signal• Second Sca nner
![Page 64: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/64.jpg)
Intercepting Analog
An amateur eavesdropper may onlyhave a single cheap receiver tofollow multiple signals
• Listens to Only a Single Side of a SingleConversation at a Time
• Misses a lot of Conversat ions
![Page 65: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/65.jpg)
Intercepting Analog
A professional eavesdropper watches311 Si;'131S in a band at the samet ime wit h a single receiver.
• May split detection and intercept operati onbetween two different systems
• Misses nothing
![Page 66: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/66.jpg)
Intercepting Digital
• Not within the Realm of a ConsumerGrade Rad io Shack Pol ice Scanner
• Often another Modified Digita l Phone• Even cheaper then a Police Scanner• Eavesdropper Programs Extra Phone as
Extension on Vict ims Cordless System• Used to " dro p in" onto exist ing ca lls
![Page 67: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/67.jpg)
Intercepting Digital
• Cheap Receiver or WLAN Card Used as aPrimitive Tuner
• Modif ied 2.4 or 5.8 GHz WLAN Card• Card Used As Tuner and Spect rum Analyzer• The I -Q Signal is Tapped• I -Q Digitized• Signal Reconstructed in Software• Basic Softwa re Defined Radio• Very High Error Rates• Narrow Bandwidth
![Page 68: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/68.jpg)
•
••.~
-••
--_.
-
•.~
'f ,e1<:,..
-
,ea"
.-....,.....""'"•••
-[~;~}:~~:.(~r[.~.J u_
... "" "-"""YH... ..,..,. ,." ,'". ," . ,..,.,,, .,, ,.,. ,.
![Page 69: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/69.jpg)
![Page 70: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/70.jpg)
![Page 71: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/71.jpg)
Why?
Eavesdropper May Not Know:• If a Cordless Phone Being Used• Where the Phone Is Located• May Not Be on a " Legal Frequency"• May Be Rarely Used• Modulation Unknown• Digita l Modu lation
![Page 72: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/72.jpg)
![Page 73: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/73.jpg)
How?
Spect rum Analyzer• Sweeps Large Segments of Spectrum• Shows Signal Spikes• Fast Detection Over Large Area• Can Miss a Signal• Extremely High Resolution of Frequency
![Page 74: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/74.jpg)
![Page 75: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/75.jpg)
How?
Instantaneous Band width Receiver• Commonly a Software Defined Radio• Grabs Entire Band of Interest• Over 30 MHz of Bandwidth is Expensive• Perfect for Band Activity Detection• Requires Secondary Hand-Off Receivers
![Page 76: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/76.jpg)
![Page 77: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/77.jpg)
![Page 78: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/78.jpg)
![Page 79: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/79.jpg)
![Page 80: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/80.jpg)
![Page 81: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/81.jpg)
![Page 82: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/82.jpg)
![Page 83: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/83.jpg)
![Page 84: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/84.jpg)
Analog Intercept Considerations
From the Spies Perspective1. Very Cheap to Eavesdrop2. Know Which Bands to Watch3. Band Edge Scans4. Spectru m Analyzer to Detect5. Hand Off to Dedicated Receivers
![Page 85: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/85.jpg)
![Page 86: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/86.jpg)
![Page 87: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/87.jpg)
![Page 88: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/88.jpg)
![Page 89: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/89.jpg)
![Page 90: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/90.jpg)
![Page 91: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/91.jpg)
![Page 92: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/92.jpg)
Advice
• Frustrate the Cordless Eavesdropper• Waste Time• Waste Resources• Lose Interest
• Keep Cordless Phone Base Station ThatYou Actually Use At a Low Height
• Keep Power Levels Really Low• Make the Spy Reall y Struggle• Less Range is Best
![Page 93: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/93.jpg)
Advice
• Use a Cord less Phone Only When YouAbsolutely Need a Wireless PhoneFor Short Periods• Mowing the Grass• Doing Yard Work• Playing wi th Dogs
• Use When Not in Cell Phone Range• Keep The Conversation Short
![Page 94: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/94.jpg)
![Page 95: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/95.jpg)
![Page 96: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/96.jpg)
![Page 97: 67.225.133.11067.225.133.110/~gbpprorg/mil/telco/dark-arts.pdf · Brief History ofCordless Phones • Invented by George Sweigert • World War II Radio Operator • Injured During](https://reader035.vdocuments.us/reader035/viewer/2022062604/5fb5d1a2f7b6b005bb040405/html5/thumbnails/97.jpg)