The 35-Type station dial. Source: The Beatrice Company Bell Labs conducted exhaustive research to determine the best methods for tone dialing. They settled on a DTMF system for the control tones ...

the dial translates rotary action to DTMF tones for the Feather FONA board inside. Far from a one-trick pony, the phone sports memory dialing, SMS messaging, and even an FM receiver. But most ...

Known as the dual-tone multifrequency (DTMF) system, the signal is a combination of the row and column frequencies of the digit key. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other ...