KEY TELEPHONE SYSTEM CALL SIGNALING AND STATION SET DATA TRANSFER ARRANGEMENT

摘要

An electronic key telephone system is disclosed in which each key telephone set is equipped with a multifrequency call signaling push-button dial as well as a number of line pick-up keys. Regardless of the number of pick-up keys on a set, it is connected to the local key system via only a single pair of tip and ring conductors and a data link. The identity of an operated pick-up key is transmitted to the local key system over the data link. The multifrequency call signaling dial is modified to generate the normal multifrequencies and in addition is connected to a digital encoder to transmit the identity of an operated call signaling push button over the data link when a certain pick-up key is operated. The local telephone system thus may dispense with the need for analog tone signaling receivers and can employ the operated push buttons for call signaling purposes in the digital mode. The station user is assured that his call signaling push buttons are operating correctly when the set is transmitting digital call signaling information to the local key system because the side tones of the multifrequency signals will be audible.