ISDNNOYUUZAA*AMIINTAAFUEESUSOCHI

摘要

PURPOSE:To attain D-channel competition control and synchronism detection in a network terminating equipment by providing this user/network interface device between the network terminating equipment and plural terminal apparatuses, copying a D-channel bit in an UP signal frame to an echo channel in an outgoing signal frame and storing and then transmitting an incoming signal frame in/from the buffer. CONSTITUTION:All terminal apparatuses 3 transmit the incoming signal frames at the synchronous timing of the outgoing signal frame transmitted from the network terminating equipment 2. A repeater 1 stores the incoming signal frames transmitted from the equipment 3 on a bus B2 in the buffer and transmits the stored frames at the prescribed timing of the outgoing signal frame to be received next. Then a D-channel bit in the incoming signal frame received in the repeater 1 is copied to an echo channel bit in the outgoing signal frame to be transmitted immediately after. Thereby even when a distance between the terminating equipment 2 and the equipment 3 exceeds a standard by CCITT recommendation, both of D-channel competition control among terminal equipment 3 and the synchronism detection of received signal frames in the network terminating set 2 can be executed.