LINE LOOPBACK CABLE IDENTIFYING SYSTEM

PURPOSE:To decrease a test time by providing a means displaying a transmission control procedure and a means displaying the content of a system generation of a line to a line loopback cable so a to compare outputs from both the means thereby checking whether or not the line loopback cable is in matching with the transmission control means. CONSTITUTION:Before a line control signal is controlled to apply line open, and a command from a host device sets the content of a transmission control procedure coded subject to system generation in a main memory or a buffer memory to a display circuit 7 through a bus control circuit 3. Further, the command is decoded by a microprocessor 2 of a line control section 100 and the content of a transmission control procedure display circuit 17 is set to a line data register 6 by controlling a bus selection circuit 11. A comparison circuit 8 checks a line loopback cable is in matching with the transmission control means or not. The result is informed to the host device 3 through the bus control circuit 3 by controlling the line control signal as to whether line open is applied or not thereby checking it in advance.