<P> By the early 1970s, Cooper headed up Motorola's communications systems division . Here he conceived of the first portable cellular phone in 1973 and led the 10 - year process of bringing it to market . Car phones had been in limited use in large U.S. cities since the 1930s but Cooper championed cellular telephony for more general personal, portable communications. . He saw the cellular phone should be a "personal telephone--something that would represent an individual so you could assign a number; not to a place, not to a desk, not to a home, but to a person ." While it has been stated Cooper's vision for the device was inspired by Captain James T. Kirk using his Communicator on the television show Star Trek, Cooper himself later said that his actual inspiration was Dick Tracy's wrist radio . </P> <P> Top management at Motorola supported Cooper's mobile phone concept, investing $100 million between 1973 and 1993 before any revenues were realized . Cooper assembled a team that designed and assembled a product in less than 90 days . That original handset, called the DynaTAC 8000x (DYNamic Adaptive Total Area Coverage) weighed 2.5 pounds (1.1 kg), measured 10 inches (25 cm) long and was dubbed "the brick" or "the shoe" phone . A very substantial part of the DynaTAC was the battery which weighed four to five times more than a modern cell phone . The phone had only 20 minutes of talk time before requiring a 10 - hour recharge but according to Cooper, "The battery lifetime wasn't really a problem because you couldn't hold that phone up for that long!" By 1983 and after four iterations, the handset was reduced to half its original weight . </P> <P> Cooper is the lead inventor named on "radio telephone system" filed on October 17, 1973, with the U.S. Patent Office and later issued as U.S. Patent 3,906,166 . John Francis Mitchell, Motorola's Chief of Portable Communication Products (and Cooper's Manager and Mentor) and the engineers who worked for Cooper and Mitchell are also named on the patent . </P> <P> On April 3, 1973, Cooper and Mitchell demonstrated two working phones to the media and to passers - by prior to walking into a scheduled press conference at the New York Hilton in midtown Manhattan . Standing on Sixth avenue near the Hilton, Cooper made the first handheld cellular phone call in public from the prototype DynaTAC . The call connected him to a base station Motorola had installed on the roof of the Burlington House (now the AllianceBernstein Building) and into the AT&T land - line telephone system . Reporters and onlookers watched as Cooper dialed the number of his chief competitor Dr. Joel S. Engel at ATT . "Joel, this is Marty . I'm calling you from a cell phone, a real handheld portable cell phone ." That public demonstration landed the DynaTAC on the July 1973 cover of Popular Science Magazine . As Cooper recalls from the experience: "I made numerous calls, including one where I crossed the street while talking to a New York radio reporter--probably one of the most dangerous things I have ever done in my life ." </P>

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