Abstract: An intercom system for use with a plurality of telephones on a single extension includes a single master station and a plurality of slave stations. The master station is connected so as to interrupt the telephone line pair to and from a central exchange. Each slave station is preferably associated with a handset that is on the extension. When the extension is not being used for intercom service or for an outside call, any telephone handset on the extension that has a keypad can initiate a signal that is received and decoded in the master unit. When the master station receives such a signal, it disconnects the line to the telephone exchange from the extension and connects the telephone exchange to a circuit that detects incoming calls so that they can be signaled to users. The master station also sends a signal to each slave station that enables the intercom function.

Abstract: A telephone set includes a coiled multi-conductor cable connected to an assembly such as a handset by a standard modular connector and an appliance is interposed in the connector to inhibit twisting of the cable. The appliance includes two parts which freely rotate relative to each other with one part receiving the male element of the connector and the other part being inserted into the female element of the connector so that, rather than the cable twisting, the parts of the appliance rotate relative to each other. The electrical connection between the conductors in the cable and conductors in the handset is maintained by cooperating contacts on the other part and on the female element and by wipers carried by one of the parts and engaging conductive rings on the other part.