As the development of mobile radio and mobile communications has gone through many technical phases, it has become common to fix these phases in generations.
The 1st generation (1G) of mobile networks was characterized by Advanced Mobile Phone System (AMPS) and Total Access Communications System
(TACS), an analog
transmission technology with circuit switching. Signaling
was analog in the first analog mobile radio networks, the A network and the B network, and already digital in the following C network.