PURPOSE:To automatically restore the titled circuit into the normal state so long as no recovery disable fault takes place in an internal circuit component in a communication terminal equipment by applying initializing to a signal control means generating signal information forcibly if a fault is detected at the access of a common signal channel. CONSTITUTION:An output Q of a flip-flop 3e is fed to a driver 5 as a driver enable (ENB)/disable (DTS) signal. With the said signal at L level, the driver 5 sends a signal from a coding section 4 to a transmission line T while driving a transmission transformer 6 and with the signal at H level, the driver 5 disconnects the communication terminal equipment from the transmission line by bringing the sent output into a high impedance state. Since a supervisory section 3 supplies a reset signal to a control section 1 in this case, the section 3 initializes a microprocessor 1a, a data link controller 1d and circuit components in the control section. Thus, even if malfunction of the microprocessor 1a takes place due to noise, the control section is restored to the initial state automatically.
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