Lifting one handset automatically started the other ringing, and cradling both devices resets it.Īpplications were the obvious “batphone” intercom between two locations, whether those be neighbours down a country road, or from the main house to the granny-flat. The intercom unit powered two telephones, allowing you to talk between them. Photocopies of that original article are still available from Silicon Chip, and they kindly let me re-publish the circuit here.
My original telephone intercom project was published in Silicon Chip magazine here in Oz in May 1992.