Remote End Initiated LBK Tests
The U-BR1TE supports loopbacks generated from the IDSL OCU-R which allow testing to be performed without coordination with the CO or test center. Loopbacks initiated by the OCU-R front panel LBK pushbutton, aid in system turn-up testing or troubleshooting from the remote end.
The U-BR1TE responds to a loopback command initiated at the OCU-R as follows:
Pressing the OCU-R LBK pushbutton once will initiate a loopback at the U-BR1TE towards the customer. See Figure 9. This allows data to be sent from the remote end to test the local loop and the IDSL OCU-R. This loopback is indicated by a flashing CUST LBK LED on the IDSL OCU-R and a solid LBK LED on the U-BR1TE.
Pressing the OCU-R LBK pushbutton a second time initiates a loopback at the OCU-R towards the 4-wire DDS (CPE) interface. A solid CUST LBK LED on the IDSL OCU-R indicates a loopback at the IDSL OCU-R towards the customer equipment.
See Figure 10. Pressing the OCU-R LBK pushbutton a third time disables all current latching loopbacks initiated by the LBK pushbutton.
If errors exist the loopbacks can help determine the source; either the local loop or the IDSL OCU-R. During a remote end initiated loopback the IDSL/DDS system transmits ASC 9Eh towards the network, indicating an out-of-service condition generated by the remote end, as shown in Figures 9 and 10.
All IDSL/DDS system latching loopbacks, whether initiated by the IDSL OCU-R craft interface, LBK pushbutton, CO, or from a remote Test Center, may be released by sending 35 DDS loop down TIP bytes <X0111010> (Where X is a “don’t care” bit.) All existing latching loopbacks may also be disabled by pressing the LBK pushbutton on the CO or remote unit.
NOTE
The remote end test feature is only supported when the upstream U-BR1TE is an ADTRAN D4 or Series 5 U-BR1TE with DDS Loopback capability. Other U-BR1TEs will ignore the loopback command sent by pressing the IDSL OCU-R LBK button.
