History of mobile phones
A cellular telephone switching plan was described by Fluhr and Nussbaum in 1973, and a cellular telephone data signaling system was described in 1977 by Hachenburg et al.
Economic history of the United States
After invention of the telephone in 1876 additional development work was required to make it commercially viable. The first telephones were for local calls. Long distance calling came into being in the 1890s, but the technology to make transcontinental calls took until 1915 to be operational.