By the early 1970s, Cooper headed 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 believed 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.