DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance for csi systems
1-71Install DS1 CPE Loopback Jack (T1 Only)
1
■3—Mode 3 Circuit
■4—Digital Communications Protocol Mod e 0 (usually the default).
NOTE:
If the ISDN-PRI trunk is of type “cbc,” make sure the TestCall Service field
on the Trunk Group Administration Form indicates the c orrect service so
that a network facility message c an be sent across the ISDN-PRI network
If the outgoing ISDN-PRI test call keeps abor ting, please make sure that the
far-end device c an handle DCP Mode 0 or DCP Mode 1.
NOTE:
Before attempting to make an ISDN-PRI test call to the public netwo rk (that
is, the network is the far-end), make sure that test call serv ice is provisioned
by the network. The user must subscrib e to Test Type 108 service and have
the correct far-end test c all number administered on the tr unk group form
for the call to be allowed.
Install DS1 CPE Loopback Jack (T1 Only)
Using the DS1 CPE Loopback Jack (ap paratus code 700A, c omcode
107988867), a technician can test the DS1 span between the system and the
network interface point. The 700A can q uickly isolate DS1 problems to either the
customer premises or to the external DS1 span.
The 700A loopback jack is required when DC power appears at the interface to
the ICSU.

The loopback jack isol ates the ICSU from the DC power and properly

loops the DC span power

. The 700A is also used when no smart jack is installed
by the local phone c ompany.
NOTE:
The loopback jack op erates with any vintage of TN767E (or later) or
TN464F (or later) DS1 circuit packs. The loopbac k jack operates with the
120A2 (or later) Integrated Channel Servic e Unit (ICSU) only;
not
the 31xx
series of CSUs, other external CSUs, or earlier ICSUs.