MONITORING DEVICE FOR TELEPHONE CALL TIME

PURPOSE:To prevent a communication circuit from being occupied by a specific terminal for a specific time or more by releasing the circuit through a network controller when a data transmitter is abnormal. CONSTITUTION:A telephone call time monitoring device 30 starts a timer mechanism by a signal 27 which indicates the start of communication from the data transmitter 20 and stops it by a signal 28 which indicates the end of the communication. The timer mechanism is preset to the specific constant time, and generates a signal 31 when entering a time-out state to command the network controller 21 to complete the communication while informing the data transmitter 20 that the telephone call time is over.