Clock rate converter – Nortel Networks 1000 User Manual
Page 978
978
NTRB21 DTI/PRI/DCH TMDI card
The NTAK20AA version of the clock controller meets AT&T Stratum 3 and
Bell Canada Node Category D specifications. The NTAK20BA version
meets CCITT stratum 4 specifications.
“Electrical specifications” (page
ATTENTION
IMPORTANT!
If an IP Expansion multi-cabinet system is equipped with digital trunk cards, it is
mandatory that at least one trunk card is placed in the Main Option 11C cabinet.
A cabinet that has a digital trunk must use a clock controller.
Digital Trunking requires synchronized clocking so that a shift in one clock
source results in an equivalent shift of the same size and direction in all
parts of the network.
On CS 1000 systems, synchronization is accomplished with the NTAK20
clock controller circuit card. The clock controller circuitry synchronizes the
CS 1000 to an external reference clock and generates and distributes the
clock to the system. The CS 1000 can function either as a slave to an
external clock or as a clocking master to the network.
The NTAK20AD version of the clock controller meets AT&T Stratum 3 and
Bell Canada Node Category D specifications. The NTAK20BD version
meets CCITT stratum 4 specifications.
“Electrical specifications” (page
ATTENTION
IMPORTANT!
Each Media Gateway that has a digital trunk must use a clock controller clocked
to an external reference clock.
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.
Clock rate converter
The 1.5 Mb clock is generated by a Phase-Locked Loop (PLL). The PLL
synchronizes the 1.5 Mb DS1 clock to the 2.56 Mb system clock through
the common multiple of 8 kHz by using the main frame synchronization
signal.
The 1.5 Mb clock is generated by a phase-locked loop (PLL). The PLL
synchronizes the 1.5 Mb DS1 clock to the 2.56 Mb system clock through
the common multiple of 8 kHz by using the main frame synchronization
signal.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
02.06
Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
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