Lucent Technologies DEFINITY Installation For Adjuncts And Peripherals page 149

DEFINITY ECS Release 8.2
Installation for Adjuncts and Peripherals 555-233-116
9 DS1/T1 CPE Loopback Jack
Loopback Testing Without a Smart Jack
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 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 numbers and pin
designations, refer to Integrated Channel Service Unit (ICSU) Installation and
Operation.
Operating Characteristics
If a TN464F or TN767E and a 120A2 were installed in a system running pre-
DEFINITY ECS, V3 software and the software is later upgraded to DEFINITY ECS,
V3 Release 3 or later, remove and re-install the DS1 circuit pack so that the ICSU
administration fields will appear on the DS1 administration screen.
Issue 1
April 2000
127