Telephone intercom circuit

A solid state intercom circuit for a telephone system in which there are a plurality of stations each of which has selective intercom access to the remaining stations of said system, comprising a sequence controller responsive to sensed conditions at said stations for initiating cycles directed toward completing calls from respective calling stations to called stations over a plurality of intercom links, a solid state switching matrix for interconnecting said calling and called stations over intercom links, a register for storing dialled digits representing a station being called, a system control circuit memory with a location for each station of said system and means for storing in said memory the status of said station and the address of a link associated with such station during an in-use condition of said station, means for scanning stations of said system, said sequence controller responsive to a station being found off-hook by said scanning means for initiating a sequence to examine the memory location associated with said off-hook station to determine its prior status and, in response to a determination that said prior status was idle, for advancing said sequence through a plurality of steps to complete a call initiated by said station.