Abstract: CPU based telephone circuitry allowing for enhanced telephone functions includes a battery backup. To minimize power drain from the battery, the battery only supplies limited circuitry required for limited telephone service without CPU support. To further limit power drain, power backup circuitry includes a first circuit limited to sensing of the hookswitch status and sensing of incoming calls and generation of a ringing sound. Based on the status of the hookswitch, additional amplifiers, dialers and the like required for the limited telephone service are then powered by the backup battery.

Abstract: In a key telephone system, when it is impossible to set at a time the entire operation data stored in a memory device of a key station unit by using a key of a specific key telephone set among a plurality of key telephone sets connected to the key station unit, the entire data of respective operation items are divided into a plurality of data sets and then the setting of the data of respective data sets are independently set. The division of the data of respective operation items is made corresponding to the output state of a hook switch, for example.

Abstract: There is disclosed a communication system and operating method wherein the manner in which all telephone calls are displayed at a station set allows uniform user operations to originate and terminate those calls. This is accomplished by having all calls dynamically assigned to the same set of general call appearances (buttons on a multibutton station set). There are no call appearances that are dedicated to specific call types. This allows the station set user to perform the same set of operations on all calls by using the same sequence of physical operations independent of the type of call. Additionally, the system may reserve one call appearance button at a station set for special use.

Abstract: An adapter circuit and system for coupling a telephone answering machine to two telephone lines. The adapter may be set so that the telephone answering machine will answer one or the other of the telephone lines, as determined by setting a mode selector switch to an "automatic" position; so that the telephone answering machine will answer only one of the telephone lines as determined by setting the mode selector switch to a "Line #1" position, or so that the telephone answering machine will answer only the other of the telephone lines by setting the mode selector switch to the "Line #2" position.