Paradyne COMSPHERE 3550 Series User Manual

Also see for Comsphere 3551: Installation manual Quick reference guide

Contents

Operating the DSU4-93550-A2-GB20-40 July 1999Test BranchThe Test branch provides extensive testing capabilitiesfor the DSU, the DDS circuit, the DBM (if installed), andthe backup circuit. When the tributary DSU receives a testrequest from the control DSU, it aborts any locallyinitiated test in progress.Running a test can affect your application data or maycause your application session to be dropped dependingupon front-end processor, time-out parameters, etc. sinceno data or acknowledgment messages will be transmittedwhile the test is in progress.AbortThe Abort selection allows you to abort a test that isrunning. The DSU cannot run any other test until the testin progress is aborted.There are two types of selections to abort a test:• Selective terminates whatever test is in progress atthe local DSU.• Subn (Subnetwork) only displays at the controlDSU. This selection terminates any test running atthe control DSU or at a tributary DSU or DBMassociated with the control.After selecting either Selective or Subn, the test isterminated and the DCP displays the message CommandComplete.Device TestThe Device (Devic) Test uses a test pattern generatorbuilt into the DSU. If a DBM is installed, the DBM mustbe in Idle mode, with no call in progress if you want to runa Device Test.NOTEOn power-up, the DSU sends outpolls to determine whether aDBM is installed. It then initiatesa Device Test on itself and theDBM. The results of the testsappear momentarily on theDCP’s LCD.LoopbackThe Loopback (Lpbk) branch displays four loopbacks:• Local Loopback (LL)• DTE Loopback (DTE)• Digital Loopback (DL)• Remote Digital Loopback (RL)Figure 4-3 shows where each loopback occurs on thecircuit. Refer to the figure as you read about loopbacks.Local LoopbackLocal Loopback (LL) is session-disruptive; that is,performing the test will disrupt data. It permits the DTE torun a test to determine whether the DTE connection to theDSU and the DSU itself are functioning properly. TheDSU must be connected to the DTE, but the networkconnection to the DSU is not required. This test cannot beperformed by the DBM.While the DSU is in Local Loopback, any datatransmission by the DTE is returned as received data. Anoperator can send a test pattern and verify correctreception of the test. The DSU does not monitor thistesting.Figure 4-3. Loopbacks