CONTROL AND INTERFACE APPARATUS FOR TELEPHONE SYSTEMS

Apparatus is disclosed for incorporation into a key telephone system control unit, in at least one station port, for operating an at least one key type set and an at least one tip and ring device simultaneously bridged onto the same station port without the use of any special service circuits or adaptors. The ability to signal alerting independently via ringing signal on a TR-pair, via messages indicating alerting transmitted on a service pair for a key set or via both techniques simultaneously is also disclosed. Further, the alerting ability disclosed in combination with control by a key system controller of the access fo a key set to voiceband communications over the TR-pair allows for incorporation of additional features into a key telephone system. These features include the following: ring specific applications relating to an external event; direct transfer of calls to the transferor station port; calling other sets on the same station port; MEWPRIC (Multiple Extension With Personal Ringing on Incoming Calls) operation, i.e., a party line type of operation where the TR device and the key set sharing a single station port of station ports 103 are assigned different endpoint addresses; prevention of "barge in", i.e., bridging, by a key type set onto a call to a TR device; time phasing of rings to allow for a coverage operation; and fax trouble detection.