DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance for csi systems
1-84LED Interpretation
1

Configurations Using Fiber Multiplexers

Use the loopback jac k when customer premises DS1 wiring c onnects to an
on-site fiber multiplexer (MUX) and allo ws wiring to the network interface p oint on
the MUX to be remotely tested. This requires that ICSUs be used o n DS1 wiring
to the MUX.
Fiber MUXes can take the place of Interfac e termination feeds as shown in
Figure 1-21, Figure 1-22, Figure 1-23, and Figure 1-24. Test these spans using
the same procedures as metallic spans. Note the following p oints:
1. Fiber MUX es may have lo opback capabilities that can be activated by the
service provider from the CO end . These may loop the signal bac k to the
CO or back to the DS1 board. If the MUX provid es the equivalent of a line
loopback on the “ problem” DS1 facility, this may be ac tivated following a
successful loopb ack jack test and used to isolate problems to the wiring
between the loopbac k jack and the MUX.
2. Be aware that there are installations that use repeatered metallic lines
between the MUX and the “dumb ” block. Theses lines req uire DC power
for the repeaters and this DC power is present at the “dumb” block
interface to the CPE equipment.

A loopback jac k is required in this

configuration to prop erly isolate and terminate the DC powe r

.
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 4)
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 4)
All measurements should read 0 (zero) volts DC. For pin num bers and pin
designations, refer to

Integrated Channel Service Unit (ICSU) Installation and

Operation

, 555-230-193.
LED Interpretation
The lighting and unlighting of LEDs indicates to the system user the status o f
various maintenance comp onents in the system. LEDS are located on the
attendant console, on all ci rcuit packs in the switc h cabinets and, op tionally, on
customer-designated voice terminals. The following LEDS are included in the
system:
■‘‘TN798 Processor Circuit Pack LEDs’’
■‘‘Attendant Console LEDs’’