4. MAINTENANCE
The ADTRAN Single-Wide FT1 Repeater requires no routine maintenance. In case of equipment malfunction, perform an in-band loopback from the central office (CO), as described in Appendix A of this practice. If a malfunction is confirmed, replace the Single-Wide FT1 Repeater.
FT1 Repeater Loopbacks
The Single-Wide FT1 Repeater has looping capability through the channel which allows for digital loopback to help isolate faults. The looping is accomplished remotely from the CO switch as described in Appendix A.
The FT1 Repeater network loopback is a digital loopback toward the CO, as illustrated in Figure 3.
Replacement of Circuit Packs
When testing indicates a faulty circuit pack, refer to the apparatus case installation/maintenance practice for the entry and pressurization control. Replace the faulty circuit pack. Request a loopback test from the CO, per Appendix A.
ADTRAN does not recommend field repair of the circuit pack. Repair services may be obtained by returning the defective unit to the ADTRAN Repair Department.
Testing the FT1 Repeater at the CO
The ADTRAN Single-Wide FT1 Repeater performs the loopback described in Appendix A.
| | | HDSL | |
| DSX-1 | | FT1 | DS1 |
| Interface | | Interface |
| FT1 DP | Repeater |
| | FT1-NID |
| | | |
| Central | | | Customer |
| Office | D4 | | Premises |
| | Local Loop | |
| | Channel Bank | |
| | | |
Figure 3. FT1 Repeater Network Loopback
This loopback is initiated by the DDS latching loopback code for NEI Position 1 (N1000001). The NEI Position 1 latching loopback is detected in the primary DS0 of the FT1 circuit (the channel in which the FT1-DP is physically installed) to control the looping of the FT1 circuit. When the FT1 circuit is looped, all DS0s in use will be looped. The DS0s in use will also be transmitted on to the customer. This loopback is also initiated from the craft interface or the LB push-button at the FT1-DP.
FT1 Self-Test
When a self-test is initiated at the FT1-DP, a repeater failure will be indicated as an FNID failure on the craft interface screens. Likewise, if a self-test is initiated at the FNID, a repeater failure will be indicated as an FT1-DP failure on the craft interface screens.
4 | Section 61245211L1-5, Issue 1 | 61245211L1-5A |