KEY TELEPHONE SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a key telephone system that conducts speech interruption connection control that takes an original speech of an interrupted side into account even when a destination number notice service is applied to a speech state interrupt incoming call service. SOLUTION: A speech available notice tone is sent to a slave unit A (2A) having an original speech 41 to inform a slave set B about a speech available state in response to a reply of the slave set B (2B) to an individual incoming call at the arrival of the individual incoming call in a form of a speech interrupting incoming call. When the slave set A (2A) hooks off accordingly, it is discriminated that the shift to an interrupting speech by a user of the slave set A (2A) is permitted and a hooking signal is sent to a telephone line 11, the slave set B (2B) is connected to the telephone line 11 to form an interruption path.