Asterisk Payphone Coin Control

Old-school Western Electric payphones required special coin control circuits to be provisioned from the central office. In addition to the normal 48V DC loop, these circuits could apply ±130V DC to trip the coin relay hopper to accept and reject coins. The central office also performed a ground test to check if initial coins had been inserted. I’d like to hack a fxo device to, with a little bit of extra hardware, expose this interface to Asterisk so that a payphone can be controlled via software.

In addition, these phones communicated long-distance coin deposits via a wonderfully boxable in-band signal. Having Asterisk/zaptel recognize these tones as well would be sweet.