LINE CONNECTION SUPERVISORY CONTROL SYSTEM

PURPOSE:To supervise a line fault after line connection by sending an in-channel control signal subjected to envelope by a data signal and an in-channel control signal while being coded into a prescribed pattern corresponding to a line control signal so as to eliminate the need for the addition of a check bit. CONSTITUTION:A line 8 is connected to a channel subjected to time division multiplex by a time division switch section 6 via a line interface section 7 and the channel and the line interface section 7 are connected by the time division switch section 6 via the transmission section 4b of other terminal equipment 2 and a trunk line 3. An in-line control signal coded by a coding section 71 is connected similarly to a decoding section 72 in a destination terminal equipment. If a fault takes place in the line connection, when the in-channel control signal is decoded by the reception destination decoding section 72, an undefined pattern is detected and informed to a system control section 5b, which informs the detection to the system control section of a central unit.