Key telephone system

Abstract

A key telephone system includes a plurality of key telephone stations, at least one of the key telephone stations being of the kind which includes CO buttons for specifying CO/PBX lines and DSS buttons for specifying the intercom designations for the key telephone stations to be interconnected via the intercom lines, and being selectively operable as a control station. The key telephone system also includes a switching network, a switching control unit and a system memory unit, the switching control unit controlling the switching network and key telephone stations in accordance with system data stored in the system memory unit. The system memory unit is provided with memory accessed by operation of DSS and CO buttons when the key telephone system is in the system data set mode. Each DSS button designates at least one memory location dedicated to the key telephone station identified by that DSS button. Each CO button designates a dedicated portion of each of the memory locations, for storing information relative to that CO line. Information relative to a CO line and designated for a particular key telephone station is set into memory by setting the control key telephone station into system data set mode, and operating the DSS button corresponding to the key telephone station to be controlled in accordance with new CO line information and by operating the CO button corresponding to the CO line about which information is to be entered into memory for the designated key telephone station. CO line information, such as ringing assignment and call restriction assignment, is thus written into memory by operating the DSS buttons designating the key telephone stations whose CO line information is to be changed, and the CO buttons to designate the specific CO lines identified for CO line information changes.