Avaya DEFINITY Server CSI Maintenance Manual page 1070

Each trunk and line have their own maintenance strategies. However, they all
depend on the health of the DS1 Interface circuit pack. Refer to the following
sections for details: TIE-DS1, CO-DS1, DID-DS1, OPS-LINE, ISDN-TRK, and
ISDN-PLK. Signaling over the DS1 link must be synchronized between the
transmitting and receiving ends to ensure error-free communication. Refer to
"SYNC (Synchronization)" for details.
The TN767E circuit pack combined with the 120A1 CSU Module forms an
Enhanced Integrated CSU. The new 120A1 CSU Module, when combined with
the functionality provided by the TN767E hardware and firmware, and new switch
software, provides functionality equivalent to an external stand-alone ESF T1
CSU. The 120A1 CSU Module connects to the TN767E circuit pack on the I/O
connector panel on the back of the port carrier. The new CSU Module, thus
becomes an integrated part of the Avaya Definity Server CSI. Throughout the
document, the term 120A1 will mean a 120A1 or later suffix CSU Module.
The Enhanced Integrated CSU is for use in the United States of America with
1.544 Mbps DS1 service. For further details on the 120A1 CSU Module see
DEFINITY. Communications System Generic 1, Generic 2, and Generic 3 V1 and
V2 - Integrated CSU Module Installation and Operation, 555-230-193.
The TN767E and 120A1 CSU Module support on-demand loopback tests that
assist in the detection of faults between the TN767E circuit pack and the CSU
Module, between the Integrated CSU and the optional Customer Premises
Loopback Jack, or between the Integrated CSU and remote CSU. These
loopback tests are explained in detail later in this DS1-BD section, but
on page 1071
The following list of acronym definitions are for
PLB = Payload Loopback
BLB = Board Loopback
ELB = Equipment Loopback
LLB = Line Loopback
RLB = Repeater Loopback
CLJ = Loopback Jack Loopback
R-LLB = Remote Line Loopback
SMRT = Smart Jack
LPBK = Loopback
For more information about DS1 interfaces, see the DEFINITY Communications
System DS1/CEPT1/ISDN-PRI Reference, 555-025-107.
1070
Issue 5 October 2002
gives a high level overview of the loopback points.
Figure 29 on page 1071:
555-233-119
Figure 29