Cellular Mobile Telephone Service


System Diagram
Frequency Allocations
Frequency Allocations
Cellular Security
Cellular Telephone Programming
Monitoring Data Streams

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Mobile radiotelephone service began in St. Louis on June 17, 1947.

Click here for more information, straight from Bell Telephone, about their mobile service in 1954.

Commercial cellular service began in the United States in October, 1983.

Service Start   City State   Ameritech Mobile
1983 October   Chicago IL   Ameritech Mobile
  December   Washington DC   Washington/Baltimore Cellular Telephone Company
      Baltimore MD   Washington/Baltimore Cellular Telephone Company
1984 February   Indianapolis IN   Indianapolis Telephone Company Mobile
  April   Washington DC   Bell Atlantic Mobile
      Baltimore MD   Bell Atlantic Mobile
      Buffalo NY   NYNEX Mobile
  May   Indianapolis IN   GTE Mobilnet
      Miami FL   BellSouth Mobility
  June   Baltimore MD   Bell Atlantic Mobile
      Buffalo NY   Buffalo Telephone Company
      Minneapolis MN   NewVector Communications
      Milwaukee WI   Milwaukee Telephone Company
      Los Angeles CA   PacTel Mobile
      New York City NY   NYNEX Mobile
  July   Minneapolis MN   MCI/Cellcom Cellular
      Philadelphia PA   Bell Atlantic Mobile
      Denver CO   NewVector Communications
      Seattle WA   NewVector Communications
      Saint Louis MO   Southwestern Bell Mobile
      Saint Louis MO   CyberTel Cellular
      Dallas TX   Southwestern Bell Mobile
  August   Milwaukee WI   Ameritech Mobile
      Kansas City KS   Southwestern Bell Mobile
      Phoenix City AZ   NewVector Communications
      New Orleans LA   BellSouth Mobility
  September   Detroit MI   Ameritech Mobile
      Houston TX   GTE Mobilenet

By the end of 1984 there were about 40,000 cellular customers.




Mobile Transmit Base Transmit Channel
824.04 - 825.00 869.04 - 870.00 991 - 1023 Voice A
825.03 - 834.36 870.03 - 879.36 1 - 312 Voice A
834.39 - 834.99 879.39 - 879.99 313 - 334 Control A
835.02 - 835.62 880.02 - 880.62 335 - 356 Control B
835.65 - 844.98 880.65 - 889.98 357 - 666 Voice B
845.01 - 846.48 890.01 - 891.48 667 - 716 Voice A
846.51 - 848.97 891.51 - 893.97 717 - 799 Voice B





Despite the best efforts of the Cellular Telephone Industry Association, it has become clear to almost everyone that there is no privacy and little security with traditional analog calls.

Migration to digital systems was supposed to give callers a "secure" capability, but such has not been the case. Based on a lot of hints from a very smart Australian, in March of 1997 a group of cryptographers announced they had broken one of three encryption systems used in one of the new digital systems. Read their announcement here.

This Candian website streams Ottawa-area analog cell phone conversations over the Internet to prove the point that these calls are in no way private.


Cellular telephones store their operating parameters in a device known as a Numeric Assignment Module (NAM). Most modern phones allow the NAM to be changed via the keypad after entering a "secret" sequence.

Sequences for a number of popular phones used to be available at the Radiophone Archive, however that site appears to be down.


Cellular control channels contain data concerning the system itself and calls that may be taking place on the network. For law enforcement personnel and cellular industry technicians, equipment is available for monitoring those channels.

Custom Computer Services offers a number of products catering to the data monitoring and locating crowd.

Electronic Countermeasures Inc. is a Canadian company offering, among other things, "Cellular and Paging Analysis Systems."

For the do-it-yourselfer, cellular data stream monitoring will require a scanner capable of tuning the 800 MHz band and access to the FM discriminator. Bill Cheek (RIP) wrote useful guide to accessing the discriminator on various receivers to extract unfiltered audio, which helps immensely in decoding data signals.

Send mail to Dan Veeneman
Updated January 28, 2006