Operation3-53510-A2-GN32-70 July 1999Model 3511 FaceplateFigure 3-2 shows the Model 3511 faceplate. Indicatorsand pushbutton switches for this DSU are listed anddescribed in Table 3-1.TestRemPassFail3511496-11884-02MultirateDSUDsblTPLLDLRLOKNS9.656/642.4/4.819.2/38.4SPEEDTXDRXDRTSCTSDSRLSD103104105106107109PUSHBUTTONSWITCHESFOR TESTINGLED INDICATORSOSStatusFigure 3-2. Model 3511 FaceplateFaceplate OperationTable 3-1 provides operation descriptions for the eightDSU status indicators, the four pairs of test switches andtest indicators, and the six DTE interface indicators forboth the 3510 and 3511 DSUs. The status indicators arealways active as long as the DSU is functioning properlyand has power; however, you can choose to disable thefour test switches via a DSU option in order to preventunauthorized testing.Diagnostic TestsUse diagnostic tests as part of the installationprocedure to verify proper operation of the DSU, and inresponse to service outages to sectionalize the failure tothe DSU, Network, or DTE.This section describes test procedures to use when allDSUs on the network are combinations of 3500 or2500 DSUs. Refer to the 2600 DSU Emulation sectionwhen testing 2600/3500 mixed networks.If the DSU timing straps (S1-1 and S1-2) have been setto a setting other than DDS, timing may change duringsome tests. Appendix B shows these changes.
