Abstract: A communications system having a common equipment unit and a plurality of telephone station sets coupled to the common equipment unit comprises a common equipment unit having at least one trunk interface for coupling at least one central office telephone line to the common equipment unit and an analog to digital converter for converting analog signals on the telephone line into digital form, and at least one station interface coupling the common equipment unit to at least one of the station sets by a single wire pair.

Abstract: A cup-shaped adapter for use in a telephone handset in receiving each of a transmitter and a receiver and in connecting a pair of conductors of a handset cord to the transmitter or receiver, comprises a boss radially extended from a peripheral surface of the adapter and a pair of arms which are approximately radially extended from the peripheral wall away from the boss and comprise outwardly directed pins. A lower housing case of the handset comprises a boss supporting member and a pair of pin supporting members which have holes and between which the arms are resiliently interposed with the pins received in the respective holes. Preferably, the boss supporting member has a central hole for receiving the boss. Alternatively, the boss supporting member comprise a pair of resilient projections which define a central opening for receiving the boss.