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.
Telephone tapping
The history of voice communication technology begins in 1876 with the invention of Alexander Graham Bell’s telephone. In the 1890s, “law enforcement agencies begin tapping wires on early telephone networks”. Remote voice communications “were carried almost exclusively by circuit-switched systems,” where telephone switches would connect wires to form a continuous circuit and disconnect the wires when the call ended). All other telephone services, such as call forwarding and message taking, were handled by human operators. However, the first computerized telephone switch was developed by Bell Labs in 1965. This got rid of standard wiretapping techniques.