There is one loopback available to the FT1 Repeaters. The FT1 Repeater Network loopback is a digital loopback toward the CO as shown in Figure A-4. The loopbacks are initiated by the DDS latching loopback codes for NEI Position 1 (N1000001) for FT1 #1 or NEI Position 2 (N100001) for FT1 Repeater # 2. The NEI latching loopback is detected in the primary DS0 of the FT1 circuit, the channel where 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.
There are two loopbacks available to the FNID. The FNID network loopback loops the FT1 signal back toward the network. The FNID CPE loopback loops the FT1 signal back toward the customer.
The FNID network loopback is a digital loopback toward the CO as illustrated in Figure A-5. This
loopback is initiated by the DDS latching loopback code for NEI Position 1 (N1000001) for a non-repeatered loop, or NEI Position 2 (N1000001) for a single repeater loop or by NEI Position 3 (N1000001) for a two repeater loop; by the craft interface when available, or by the REM LBK button at the FT1 DP. 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 be filled with all 1s and transmitted toward the customer.
The FNID CPE loopback is a digital loopback toward customer premises as shown in Figure A-6. This loopback is initiated by the craft interface, when available. When the FT1 circuit is looped, all DS0s in use will be looped. The data in the DS0s in use will be transmitted toward the network.
DSX-1
Interface
Central Office
DS1
Interface
Customer Premises
Figure A-4. FT1 Repeater # 1 or 2 Network Loopback
DSX-1
Interface
Central Office
DS1
Interface
Customer Premises
Figure A-5. FNID Network Loopback
DSX-1
Interface
Central Office
DS1
Interface
Customer Premises
Figure A-6. FNID CPE Loopback
A-2 | Section 61245201L1-5, Issue 3 | 61245201L1-5C |