ADTRAN TR OCU DP Installation And Maintenance Practice

Contents

ADTRAN TR OCU DP Installation And Maintenance Practice Manual pdf 14 page image

Total Reach Office Channel Unit Data Port Installation and Maintenance Practice8 61292006L1-5CFalse Loopback ImmunityThe ADTRAN Protected Loopback family of channel units includes an algorithm compatiblewith SARTS® , Hekimian ® , TPI ®, and other test systems that virtually eliminates false latchingloopbacks. Immunity is automatically enabled at a data rate of 64 kbps. Additionally, theADTRAN Protected Loopback family features a “Protected Loopback” mode for further falselatching loopback protection.Protected LoopbackThe ADTRAN Protected Loopback supports the DDS latching loopback standard in T1E1.2/99-007R1. When protected loopback is enabled, the TR OCU DP responds to latchingloopback when the idle code preamble is sent prior to the latching loopback sequencespecified in TR62310 and ANSI T1.107. Protected loopback prevents false latching loopbackswhen the loopback sequence is embedded in customer payload data. Test equipment shouldsupport T1E1.2/99-007R1 to perform testing at a data rate of 64 kbps when protectedloopback is enabled. Refer to Table 4 for the latching loopback sequence requirement whenprotected loopback is enabled.Note: Minimum of 35 TIP bytes required to disable established latching loopback.Note: X = Don't care bitTable 4. Protected Loopback Mode Requirement T1E1.2/99-007R1(Latching Loopback)Sequence Function Byte Code Number of Received BytesExit data protocol Idle - 11111110 Minimum of 35 Idle bytesClear existing loopbacks Transition in progress (TIP)X0111010Minimum of 35 TIP bytesIdentify device to be looped Loopback select code (LSC)X1010101 - OCUX0110001 - CSUX1000001 - NEIMinimum of 35 LSC bytesPrepare to loop; send MAP codeafter 30 bytesLoopback enabled (LBE)X1010110Minimum of 100 LBE bytesActivate loopback Far-End voice (FEV)X1011010Minimum of 32 FEV bytes