Nortel Communication Server 1000S Installation And Configuration Manual page 336

Page 336 of 394
553-3001-201 Standard 2.00
2.0 Mb PRI implementation
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 systems, synchronization is accomplished with the
NTAK20 clock controller circuit card.
Every Small System cabinet or MG 1000S that contains a digital trunk
must contain a clock controller. If a Small System is equipped with digital
trunks, Nortel Networks recommends that at least one digital trunk is
placed in the Small System main cabinet.
The Clock Controller circuitry synchronizes the system to an external
reference clock, and generates and distributes the clock to the system. The
system can function either as a slave to an external clock or as a clocking
master. The NTAK20AB version of the clock controller meets AT&T
Stratum 3 and Bell Canada Node Category D specifications. The
NTAK20BB version meets CCITT stratum 4 specifications.
Shelf slot assignment
On non-CISPR B system cabinets, the NTAK20 is placed in slots 1-9. On
cabinets NTAK11Dx and NTAK11Fx, the active NTAK20 is placed in slots
1-3 (slots 4-10 cannot be used.) On IP Expansion cabinets, the NTAK20 is
placed in slots 11-19, 21-29, 31-39, 41-49 of the first, second, third, and
fourth expansion cabinets, respectively.
For CS 1000S, it is installed in slots 11-14, 21-24, 31-34, 41-44 of the first,
second, third and fourth MG 1000S, respectively.
Note: For CS 1000S, physical card slots are numbered 1-4 on the first,
second, third and fourth MG 1000S.
September 2004
IMPORTANT!