TRANSMISSION FAILURE PROCESSING METHOD FOR LOOP TYPE TRANSMISSION UNIT

摘要

PURPOSE:To protect the degradation of the responsiveness of data transmission by extending link quality monitoring time in conformity with the duration of a sound state of transmission route for enhancing the detecting performance of a loop type transmission unit for intermittent transmission failure. CONSTITUTION:In a transition from the active state (PC5) to the disable state (PC2), the PCM discriminates whether the duration T-LA of a sound state of transmission route exceeds a reference value BLIMIT1 or not. If the duration is less than the reference value BLIMIT1, a link quality monitoring period of time TLINK is doubled. In a test state (PC3), the PCM uses a link quality monitoring period of time TLINK to discriminate the transmission quality of transmission route 11. Therefore, if a transmission faiure occurs before the duration T-LA of an active state (PC5) reaches a reference value BLIMIT1, the link quality monitoring period of time TLINK is extended double by double.