Abstract: A method and system for interconnecting a telephone system and an intercom system. In one exemplary embodiment, telephone switchgear is connected to a telephone interface which provides separate voice transmit and receive channels. For example, an E&M tie line module can be utilized, which also includes E&M signaling connections for signaling an incoming intercom call to a telephone and for signaling an outgoing telephone call to an intercom. In this exemplary embodiment, an interface circuit is also provided to allow for signal level adjustment along the transmit and receive channels, such that the signal gain of the telephone system can differ from the signal gain of the intercom system. The interface circuit can include a controller which controls a switching device for selectively allowing communication along the transmit and receive channels during periods when communication is desired.