PURPOSE: To diagnose the transmission/reception characteristic quality of a master machine by comparing the reception characteristic initial value of the master machine, which is stored based on a master machine diagnostic request by a line controller, with a reception characteristic value at the time of attaching an attachable/detachable part of the master machine again after temporary detachment.
CONSTITUTION: A master machine 11 has the attachable/detachable part and a fixed installation part which has an attached/detached state detecting function to detect the attached/detached state of this attachable/detachable part. For the purpose of performing maintenance, an interlocking switch 14a is turned on before an optical transmitter unit 15 or an optical transmitter/receiver unit 18 is detached from a fixed unit 14 to disassemble the master machine 11. After the end of maintenance, the position of the switch 14a is returned to the original position, and a control circuit 23 operates the self-diagnostic function and stores the result in an internal storage circuit as the initial value. A line controller 5 stores the reception characteristic initial value of the master machine 11 based on the self-diagnostic request code of a slave machine and compares it with the reception characteristic value to diagnose the transmission/ reception characteristic quality of the master machine 11.
HIROHASHI KAZUTOSHI
SAKAMOTO ATSUSHI
KUMAGAI NOBUAKI
OSUGI KAZUHIRO
