In the early 1920s the Detroit Police Department was the first government agency to use mobile radiotelephones in their patrol cars. At this time only one-way service was available, the pertinent information could be sent to the police vehicle but no response to the call was possible. Some five years later two-way service was introduced by a police department in New Jersey. This capability was then also made available for those private citizens that could …
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showed last 75 words of 560 total
…created to set realistic goals for cellular phone providers and research new technologies for cell phone development. The Telecommunications Industry Association set a new standard with the creation of the TDMA Interim Standard 54, in 1991. Since that time, three new technologies have evolved into industry standards for cell phone telecommunications: TDMA IS-136, CDMA IS-95 and GSM. TDMA IS-136 and CDMA IS-95 are both widely spread in the United States. GSM has become the standard in Europe.