Abstract: A telephone set 2 to be connected to a main unit 1 of a private branch exchange or a key service unit includes therein a verbal telephone directory memory section 28d which stores information relating to the voice of the user and information relating to telephone numbers, a control section 28a which recognizes the user's input voice on the basis of the voice information and controls a dialing operation on the basis of the phone-number information, and a predetermined guidance memory section 28c which stores predetermined guidance used for giving instructions to the user in the form of voice or an indication.

Abstract: A telephone-system interface circuit connected to a central office via a tip line and a ring line includes a battery having a first terminal and a second terminal. A first current control circuit is connected between the tip line and the first terminal of the battery. A second current control circuit is connected between the ring line and the second terminal of the battery. The first current control circuit and the second current control circuit are equal in structure.

Abstract: A calling signal controller in which a calling signal generator having a necessary and minimum output capacity is used to the most efficiently possible extent. The controller includes a phase number memory specifying the total number of phases of calling signals used to selectively call a plurality of telephone sets, a ringing count memory loaded with a ring count for each of the phases, and a ringing control memory of which addresses are associated with the phase numbers and the ringing counts, thereby controlling the calling signals.