The database which stores the many multimedia information which it should transmit to circuit interface and

摘要

PURPOSE: To automatically and early discover a line abnormality by providing a line interface detection circuit with a line check program memory, a monitoring circuit for confirming the presence or absence of the incoming call to a line interface and a line interface inspection circuit for inspecting the presence or absence of a line abnormality. CONSTITUTION: When the incoming call to a line interface 13-1 corresponding to prescribed monitoring time within this prescribed time is not detected in an incoming call monitoring circuit 22-1, a prescribed check command signal is transmitted. An abnormality inspection circuit 23-1 transmits a signal to check the line interface 13-1 to a line control part 11 based on this check command signal. The line control part 11 reads a line check program from a ROM 21 and performs a series of inspections for the line interface 13-1 and the system in accordance with this program. If the incoming call is not detected even if test communication is performed for the line interface 13-1, the line interface is regarded as abnormal. Thus, the presence or absence of the abnormality is automatically confirmed.