Common Systems Connection Standards AT&T Services, Inc
Date: August 31, 2007 ATT-TP-76450, Issue 9
Copyright ©2004 – 2006, AT&T Knowledge Ventures
All rights reserved
Page 13
office BITS, with primary and secondary DS1 (or Composite Clock) reference signals from
separate T1 (DS1) or Composite Clock (CC) output cards, with odd-even slot, alternate group
assignments. The ability to access, test and validate timing is critical to maintaining and
administering a sync network. AT&T approved wire-wrap pins/points for Tip, Ring & Shield
connections are most important and a prerequisite for test access for troubleshooting, analyses
and diagnostic purposes. To be effective as a test point the approved wire-wrap pins must be
mechanically, physically and electrically integrated into the network element hardware
(backplane, chassis) to provide those test access points. The Tip & Ring terminations for DS1
signals electrically must be 100 Ohms resistive with +/- 10 % tolerance. The Tip & Ring
terminations for Composite Clock signals electrically must be 133 Ohms resistive with +/- 10%
tolerance; paralleling 100 Ohms resistive with 100 Ohm AC impedance terminations is not
permitted. The shield lead is “DC” grounded where the signal originates.
3.5 Output card exhaustion
In the event of T1 (DS1) or Composite Clock (CC) output card exhaustion, daisy-chaining to
enable cascading of synchronization to all terminals within a bay framework is not an AT&T
company’s standard and shall not be permitted. Arrangements must be made to install
additional BITS outputs. Should there be a necessity for more timing outputs than can be
supplied by a single TSG, multiple TSGs timed directly from the Master (or its directly
associated expansions) may be required. The subtending (or remote expansion) TSGs must
remain phase aligned with the office master TSG. To achieve and sustain phase alignment, the
subtending TSGs must be timed from the master ensemble via redundant Composite Clock
signals. The subtending TSG must have the characteristic that it will remain tightly phase-
locked with the master TSG to ensure proper DS0 phase alignment throughout the office.
4 Alarms
4.1 Equipment surveillance is performed at two levels, remote surveillance and local
surveillance.
• Remote surveillance - Involves providing Alarm, Status and Control (AS&C) capabilities
for central office equipment to a remotely located surveillance center. Remote
surveillance interfaces are well-defined and supported in all AT&T regions.
• Local surveillance - Involves the annunciation of the local central office equipment
audible and visual alarm indications within the central office.
4.2 Local and Telemetry Alarms
• All equipment (Network Elements - NE) deployed in a Central Office must have the
capability of providing both local and telemetry alarm outputs for failed and threshold
activities.
