Testing7-4 7612-A2-GB20-00June 1997DSU or Internal Network LoopbackDSU loopback is an internal loopback that is located as close as possible to thecustomer interface serving the DTE.An active DSU loopback initiated from the network disrupts IP data going over theIMC. However, this test is not disruptive when initiated by the user (via ATI) or bythe NMS.DSU CSUDTEInterfaceAggregateDTEPortDDSNetworkPort496-15160DSU LoopbackSend V.54 Up/Down SequencesThe local DSU can send an ITU-T V.54 Up or Down sequence to request theactivation or termination of a DSU (digital) loopback of a remote unit. This is thesame as the DSU Loopback shown above except the test is activated remotely.The DSU can send: In-band V.54 Up (activation) code to request a Remote DSU Loopback(V.54 Loop 2) at the remote DSU, or In-band V.54 Down (deactivation) code to request the termination of aRemote DSU Loopback (V.54 Loop 2) at the remote DSUTo initiate a send sequence, select the appropriate Send command. Sendingappears in the Status column followed (after 3 seconds) by Command Completeat the bottom of the screen.511 Test Pattern for the NetworkThis test sends and/or monitors the 511 test pattern over the network interface.The Monitor 511 test also provides an error counter that can be reset.To start sending and/or monitoring, select the appropriate Start command.
