Section 5, User Interface Guide - UIG-530, M13 Loopbacks61186003L1-1D 5-85Data ModeSelect the Data Mode option to end a test in progress.TributaryA Tributary loopback loops the selected T1/E1 back to the DS3 network. The T1/E1 signal isdemultiplexed through the M23 and M12/G.747 demultiplexers, looped back, and multi-plexed back up through the M12/G.747 and M23 multiplexers. During this loopback, allnetwork receive data is passed to the DSX-1/E1 transmitters, but all data received by theDSX-1/E1 loop side is ignored and substituted with the network data. Figure 5-52 providesan illustration of this test.Figure 5-52. Tributary Loopback TestAnalog NetworkAn Analog Network loopback test loops the selected T1/E1 back to the DS3 network. The T1/E1 signal is completely demultiplexed, looped back at the T1/E1 line interface unit (LIU),through the LIU drivers and receivers, and multiplexed back onto the DS3 network stream.Figure 5-53 provides an illustration of this test.Figure 5-53. Analog Network Loopback Test DSX-3LIUCODEC(1 of 28)CODEC(28 of 28)M23MUX/DMUXDS3FRAMERM12/G.747MUX/DMUX(1 OF 7)DS2FRAMERT1/E1 LIU(1 of 28)T1/E1 LIU(28 of 28)
