Avaya 555-233-116 manual Configurations using fiber multiplexers

DS1/T1 CPE loopback jack

Configurations using fiber multiplexers

Use the loopback jack when customer premises DS1 wiring connects to an on-site fiber multiplexer (MUX) and allows wiring to the network interface point on the MUX to be remotely tested. For a G700 Media Gateway, this requires that the MM710 CSU be set so it can be used on DS1 wiring to the MUX.

Fiber MUXs can take the place of Interface termination feeds as shown in Figure 24 through Figure 31. Test these spans using the same procedures as metallic spans. Note the following points:

1.Fiber MUXs may have loopback capabilities that can the service provider can activate from the CO end. These may loop the signal back to the CO or back to the DS1 board. If the MUX provides the equivalent of a line loopback on the “problem” DS1 facility, activate it after a successful loopback jack test, and use it to isolate problems to the wiring between the loopback jack and the MUX.

2.Be aware that there are installations that use repeatered metallic lines between the MUX and the “dumb” block. These lines require DC power for the repeaters and this DC power is present at the “dumb” block interface to the CPE equipment. A loopback jack is required in this configuration to properly isolate and terminate the DC power.

To check for the presence of DC, make the following 4 measurements at the network interface jack:

1.From transmit tip (T, Pin 5) to receive tip (T1, Pin 2)

2.From transmit ring (R, Pin 4) to receive ring (R1, Pin 1)

3.From transmit tip (T, Pin 5) to transmit ring (R, Pin 4)

4.From receive tip (T1, Pin 2) to receive ring (R1, Pin 1)

All measurements should read 0 (zero) volts DC. For pin numbers and pin designations, refer to Integrated Channel Service Unit (ICSU) Installation and Operation.

156 Issue 4 October 2002 555-233-116