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DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si
555-230-127
Issue 1
August 1997
Maintenance Object Repair Procedures
Page 10-476DS1-BD (DS1 Interface Circuit Pack)
10
The TN767E circuit pack combined with AT&T’s new 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
AT&T 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 DEFINITY. system. 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 Figure
10-28 gives a high level overview of the loopback points.
The following list of acronym definitions are for Figure 10-28:
■ 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.