TRANSMISSION LINE ERROR TEST METHOD VIA LOOPBACK AND MULTIPLEX COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To specify a faulty station by performing a transmission line error test without using any measuring device by calculating a transmission error based on the loopback data which are inserted into an extra bit. SOLUTION: The loopback data are inserted into an extra bit of the data sent from a local multiplexing device 1 and then transmitted. A remote multiplexing device 2 returns the received loopback data as an extra bit and also calculates an error rate from the loopback data. Then the error rate is inserted into an extra bit other than that where the loopback data are inserted and transmitted to the device 1. The device 1 decides an error rate and diagnoses the fault directions of up and down links based on the extra bit where the loopback data are inserted and the extra bit where the error rate calculated by the device 2 is inserted.