American Telecom AM64/128A manual Remote Loop from menu, Rem Loop Off, Rem Loop On

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Test Menu	AM64/128A User Manual

With a G.703 interface fitted, the application of a loopback will apply a loopback to line at the remote slave unit (known as an LTU loop on the G.703 linecard and standalone units).

Note : It is not possible to “Hardwire” a G.703 loop at the G.703 interface connector.

5.4.3. Remote Loop

Remote loop involves turning on a BBM loopback, but from the other end of the link (see figure 5.4.3).

This can only be menu activated from a BBM with a X.21bis interface. It is available from the DTE however, in either X.21 or X.21bis.

5.4.3.1 Remote Loop from menu

On applying the loop, the TM LED should light and the top level status display should show ‘Loop Active’.

To apply the loop select the item

T> Rem Loop Off

Press SELECT and the display should change to

T> Rem Loop On

Note: As this feature applies a loop at the remote end, it is possible that in some circumstances (mainly fault conditions) that the actual loop can be removed without the local BBM realising it. In these cases the display will show Rem Loop On when in fact no loop exists. If the loop has been cleared by a transient fault condition it can of course be reapplied by deselecting the Remote loop and then re-selecting it. The data flow with the loop applied is as shown in figure 5.4.3.

Note : In order to apply a remote loop back to line at the remote end of a BBM to BBM link from the local

end, when operating with an X.21 or G.703 interface at an unstructured rate ie : 64kbps (bit or byte timing) or 128kbps, use the communication channel loop back (see section 5.4.9).

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Contents ATL Part No /203/002/610 Issue 4 September Base Band ModemInformation Contained This Document is Confidential to Contents Appendix B Introduction International ModelsInterface Modules Constructional DetailsBaseband Modems System Overview System Overview Installation TestingBBM to BBM Link Self Test PassLTU Ready No Alarm LTU Not Ready Link ModeNetwork Mode BBM to Line Card LinkFront Panel Features Menu OperationLoop back Off Loop back OnLoop Active Status MenuOver all Status Alarm Status No Alarm No Signal Receiving AIS No AlignmentLOS/CD Fail CD FailInterface Status User RateLine Rate Operating Mode Link Mode Network ModeTest Menu Local loopLocal loop from menu Top level display shows Loc Loop Off Loc Loop OnLoopback Local loop from DTELoopback is applied by selecting the display Loopback Off Loopback OnRemote Loop Remote Loop from menuRem Loop Off Rem Loop OnBin Keys Off Sending Bin Binary PatternsRemote loop from DTE Error Count Bit Error Rate BER = User Data Rate x Time Data TestOverview OperationErrors nnnnnn Errors s000001Errors Data TestInjection Mode Transparent ModeInjecting 0s Injecting 1sService Test Svc TestComms Evp Rx Evp Tx Time If the count is stopped the display is StopLamp Test Self TestCommunication Channel Loopback Comm Loop OffRate Menu Rate 4.8KMaster 64K BT Slave 4.8K Option Menu 2 X.21bis3 G.703 Asynchronous ModeSignalling Rate Character Length Char LenLine Rate Configuration MenuMaster Slave Synchronisation Type for software versions below 3 X.21 Loop ControlModem Synchronisation Type for software version V1.3 and above Ext Byte ClkExt Bit Clk Internal ClkMenu Lock 5 64k ModePower Level Glossary of Terms Band circuits General Specifications Appendix a Interface Pin Connections Way D type X.21 bis V.24 / V.28* Connector pin allocationWay D-type X.21 V.11 Connector pin allocation Mrac Connector Pin allocation Way D-type V.36 Connector pin allocationWay D-type RS-530 Connector pin allocation Line ConnectorAppendix B Internal Link Settings Page Interface Modules Interface ModuleRS530 Interface Module 21bis Interface ModuleService Test Facilities Frame StructureAppendix C In Service Test LVD Safety Statements TTE Network and Safety statementsAppendix E 21 bit timing cable 15 way to 15 way D type plugs35 bit timing cable 34 way to 34 way Mrac plugs 21 byte timing cable 15 way to 15 way D type plugs24 / V.28 bit timing cable 25 way to 25 way D type plugs 21 bis V.36 bit timing cable 37 way to 37 way D type plugs RS530 bit timing cable 25 way to 25 way D type plugsAppendix F Troubleshooting Slave Mode 64K Rate Power 10dBmMaster Mode C 64K Rate Rate 64K