In 1949, AT&T commercialized Mobile Telephone Service. At the time, only approximately 5,000 customers had the service. Calls required manual assistance by an operator. The call subscriber equipment weighed about 80 lb and required the use of a vehicle to make it mobile, and was therefore considered a car phone. Similar to a modern day Walkie-Talkie, a button had to be held down on the handset to talk and then released to listen.
The first car telephones connected to the Public Switched Telephone Network in the United States were put into service in 1946, as a response to the growing mobility of the American population in the postwar years. Initial design of the mobile telephone itself was undertaken by the Western Electric Corporation, the prime supplier of telephone sets to the nation’s Bell System operating companies, while Bell Laboratories itself designed the overall system and set the specifications for the equipment. At the same time, the independent telephone companies were developing their own equipment, to be supplied by Automatic Electric. The Bell System equipment built upon an already existing mobile radio set, Western Electric’s 1945 vintage Type 38 or 39 VHF FM police radio equipment, adding a telephone style handset and a selective calling decoder, which rang a bell in the automobile when that phone’s unique number was signaled. The selective calling decoder consisted of a small wheel in a glass enclosure, with pins located at certain points around its circumference. The decoder had been developed in the 19th century for railway right-of-way signaling, was later used in ship to shore radio telephone installations in the 1930’s, and was a proven concept. This decoder was labeled “102.” Western Electric and the Bell companies thus did not draw up an entirely new concept for a car telephone in 1946; they used proven components of other systems to create the new public car telephone service.
Mobile telephone equipment had already been in use internally within the Bell System on an experimental basis, going back before WWII, using mobile radios such as the Western Electric Type 28 VHF equipment. One example was the Emergency Radiotelephone Service established by New York Telephone in December, 1940, which used AM on the 30-40 Megacycle band. Based on the successful tests of that equipment, AT&T announced the creation of the General Mobile Radiotelephone Service on June 29, 1945, and applied to the FCC for authority to establish base stations in Baltimore, Chicago, Cincinnati, Milwaukee, Philadelphia, Pittsburgh, St. Louis, Washington DC, Columbus Ohio, Denver, Houston, New York City, and Salt Lake City. One has to wonder why nothing was initially considered for California.
The FCC and the Bell companies envisioned two forms of mobile telephone service, “HIGHWAY” and “URBAN.” Both would be VHF, and both would use FM. The “Highway” service, as its name implies, was intended primarily to serve the major land and water routes that existed across the United States in the 1940’s, which would not be served by the “Urban” systems. Highway service was intended for trucks and barges on inland waterways rather than private vehicles. Highway service was allocated 12 channels in the VHF “low band,” with the mobile equipment receiving on 35 Megacycle and transmitting on 43 Megacycle frequencies, although not all 12 channels were initially used. The Urban equipment, as its name implies, was intended to serve mobile subscribers whose travels took them primarily within the immediate radius of a major urban center, such as doctors, delivery trucks, ambulances, newspaper reporters and so forth. Urban equipment operated on VHF 152 Megacycles (receive) and 158 Megacycles (transmit,) and the initial FCC allocation in 1946 was for 6 channels. The separation in transmit and receive channels was necessary to provide a “half duplex” communications circuit, and allowed the telephone company base station to remain on the air continuously during the duration of the call. The first Highway system went on the air in August 28, 1946 in Green Bay, Wisconsin, and the first Urban system went on the air in Saint Louis on June 17, 1946.
By 1948, Urban service was available in 60 cities in the United States and Canada, with 4000 mobile subscribers, handling 117,000 calls per month. Highway service was in place in 85 cities with 1900 mobile subscribers, handling approximately 36,000 calls per month, with most major highways in the east and Midwest covered.
The Bell System also entered the two-way business and police radio market after the war by offering the rental of entire radio systems including their maintenance and updating. This equipment was marked “Bell System” either in white painted letters or with water-slide decals. Smaller police departments were encouraged to use the “Urban” mobile telephone system as opposed to a traditional dispatch system, which must have been somewhat odd in operation. Most of the equipment rented by the Bell System affiliates was Motorola two-piece “Deluxe” equipment, FMTRU-5V “Dispatcher” and GE one-piece pre-Progress Line radios. It is believed that the Bell System discontinued this practice sometime in the early to mid 1950’s.
One thought on “First car phone electronics, 1946.”
Very col. Thank you.