Key telephone interface

Abstract

Apparatus is disclosed for use in a key set interface to overcome the incompatibility between key sets and tip and ring devices. The interface apparatus rejects ringing voltage and tip and ring loop current intended to be supplied on a first pair of conductors, the TR-pair. The interface further includes apparatus adapted for bi-directional communication of supervisory and control signals. In a preferred embodiment of the invention, a second pair of conductors, the service pair, transports bi-directional supervisory and control signals as well as operating power supplied by a key system controller for non-TR devices. Additionally, a transceiver adapted for sending and receiving voiceband information over the first pair of conductors is incorporated into the interface. An advantage of this key set interface is that operation of a key telephone set does not interfere with the operation of a tip and ring device bridged onto the first conductor pair.

Dependencies are inferred from the claim text.