American Telecom AM64/128A manual Local loop from DTE, Loopback On

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AM64/128A User Manual	Test Menu

With a G.703 Interface fitted, the application of a local loop will cause G.703 data to be looped back to the G.703 network at the G.703 interface (known as a Loop B / LCB loop on the G.703 linecard and standalone units) as shown in figure 5.4.1.2 below.

5.4.1.2 Local loop from DTE

To apply a local loop in this fashion refer to your DTE equipment handbook for details on how to send the pattern. The BBM can be in any menu when this loop is applied, it does not have to be in the Test Menu. Note : The Test Menu ‘Loc Loop’ message does not reflect the state of a loop applied from the DTE, but the status menu display and the TM LED will be set as in the diagram figure 5.4.1.1.

It is possible to have a BBM Menu selected local loop operational at the same time as a DTE local loop. In this case the local loop will only be removed when both the Menu item has been deselected and the DTE has cancelled its loop, (i.e. the loop is removed by the last releasing action).

5.4.2 Loopback

The loopback feature places a loop on the local BBM in the opposite sense to the local loop, i.e. data coming from the line is looped back. The DTE is effectively cut off and receives a Not Ready signal.

Loopback is applied by selecting the display:		T > Loopback Off


Pressing SELECT activates the loop, indicated by:			T > Loopback On

The TM LED should then light and the top level status display should show ‘Loop Active’. The data flow for this loop is shown in fig 5.4.2.1 below :

This loop cannot be activated from the local DTE, only by the remote DTE, and in this case it is termed a Remote Loop, (see section 5.4.3).

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Contents Base Band Modem ATL Part No /203/002/610 Issue 4 SeptemberInformation Contained This Document is Confidential to Contents Appendix B International Models IntroductionBaseband Modems Constructional DetailsInterface Modules System Overview System Overview Self Test Pass InstallationTesting BBM to BBM LinkLink Mode LTU Ready No Alarm LTU Not ReadyBBM to Line Card Link Network ModeMenu Operation Front Panel FeaturesLoop back On Loop back OffOver all Status Status MenuLoop Active CD Fail Alarm StatusNo Alarm No Signal Receiving AIS No Alignment LOS/CD FailLine Rate User RateInterface Status Link Mode Network Mode Operating ModeLoc Loop On Test MenuLocal loop Local loop from menu Top level display shows Loc Loop OffLoopback On LoopbackLocal loop from DTE Loopback is applied by selecting the display Loopback OffRem Loop On Remote LoopRemote Loop from menu Rem Loop OffRemote loop from DTE Binary PatternsBin Keys Off Sending Bin Operation Error Count Bit Error Rate BER = User Data Rate x TimeData Test OverviewData Test Errors nnnnnnErrors s000001 ErrorsInjecting 1s Injection ModeTransparent Mode Injecting 0sTime If the count is stopped the display is Stop Service TestSvc Test Comms Evp Rx Evp TxSelf Test Lamp TestComm Loop Off Communication Channel LoopbackRate 4.8K Rate MenuMaster 64K BT Slave 4.8K 2 X.21bis Option MenuSignalling Rate Asynchronous Mode3 G.703 Char Len Character LengthMaster Slave Configuration MenuLine Rate Modem 3 X.21 Loop ControlSynchronisation Type for software versions below Internal Clk Synchronisation Type for software version V1.3 and aboveExt Byte Clk Ext Bit ClkPower Level 5 64k ModeMenu Lock Glossary of Terms Band circuits General Specifications Way D-type X.21 V.11 Connector pin allocation Way D type X.21 bis V.24 / V.28* Connector pin allocationAppendix a Interface Pin Connections Way D-type V.36 Connector pin allocation Mrac Connector Pin allocationLine Connector Way D-type RS-530 Connector pin allocationAppendix B Internal Link Settings Page Interface Module Interface Modules21bis Interface Module RS530 Interface ModuleFrame Structure Service Test FacilitiesAppendix C In Service Test TTE Network and Safety statements LVD Safety Statements21 bit timing cable 15 way to 15 way D type plugs Appendix E24 / V.28 bit timing cable 25 way to 25 way D type plugs 21 byte timing cable 15 way to 15 way D type plugs35 bit timing cable 34 way to 34 way Mrac plugs RS530 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 plugsAppendix F Troubleshooting Rate 64K Slave Mode 64K RatePower 10dBm Master Mode C 64K Rate