HowTo: Running the 1G Analog Phone from 1997
Analog mobile phones were popular in the 90s and the last operators ended their service only in 2007. Is it possible to run this phone now? Let’s figure it out.
AMPS
Advanced Mobile Phone System (AMPS) standard was created by Bell Labs in 1983, these phones became popular in the 90s. This standard was a sort of first-generation cellular technology — the voice was transmitted using the “old way” method of frequency modulation (FM), like in a walkie-talkie radio, but the radio spectrum was divided into separated channels, and the so-called “control channel” was actually digital.
The AMPS is using 825–845 MHz and 870–890 MHz frequency bands, the spectrum is divided into 21 control channel and 395 traffic channels. Each client is assigned a separate channel for a single cellular phone call. Some modern features, like roaming, were also available, and the process of dialling the phone number was easy and not too much different from modern phones in the XXI century. The biggest disadvantage of the AMPS was the analog voice transmission — every phone call can be overheard by using the radio receiver, capable to be tuned to these frequencies, and as we know nowadays, some journalists were actually doing this, trying to sniff out other people’s secrets. On the other side, in the 80s the microcontrollers just did not have…
