Clocking Modes - Avaya Nortel Communication Server 1000 Reference

NTDW12AAE5 Universal Clock Controller daughter board
Note:
NTDW12AAE5 Universal Clock Controller daughter board and the NTAK20 Clock Controller
daughter board can be used in different cabinets within the same CS 1000 Small system/
CS 1000E cabinet.
Note:
The NTDW12AAE5 Universal Clock Controller daughter board mounted on the
NTDW79AAE5 UDT E1/T1 card can be used as the clock controller card serving other Nortel
digital trunk cards (e.g. NTBK50, NTAK09) within the same CS 1000 Small system/ CS
1000E cabinet.
Note:
Existing Nortel digital trunk cards (e.g. NTBK50, NTAK09) can be used as the Secondary
clock reference for the NTDW12AAE5 Universal Clock Controller daughter board.
Note:
Clocking slips can occur between systems that are clocked from different COs, if the COs
are not synchronized. The slips can degrade voice quality.
The clock controller circuitry synchronizes the CS 1000 system to an external reference clock
and generates and distributes the clock to the system. The CS 1000 system can function either
as a slave to an external clock or as a clocking master. The Universal clock controller meets
the AT&T Stratum 3 and Bell Canada Node Category D specifications and CCITT Stratum 4
specifications.
The Universal clock controller performs the following functions:
• phase lock to a reference, generation of the 160 Khz system clock, and distribution of the
clock to the CPU through the backplane
• accept one primary and one secondary reference
• primary-to-secondary switchover and auto-recovery
• chatter prevention due to repeated switching
• error-burst detection and correction, holdover, and free running capabilities
• communication with software
• jitter filtering
• use of an algorithm to detect crystal aging and qualify clocking information

Clocking modes

The CS 1000 supports a single clock controller that can operate in one of two modes: tracking
or non-tracking (also known as free-run).
586 Circuit Card Reference
Comments? infodev@avaya.com
July 2011