Nortel 1000 Installation And Commissioning Manual page 260

260 2.0 Mb PRI implementation
If the NTAK93 D-channel daughterboard is attached, the NTBK50 PRI card
functions in the same manner as the NTAK79 PRI card. If the NTBK51
D-channel daughterboard is attached, software is downloaded to the card
instead of residing in a D-channel circuit.
For information on the NTBK50 faceplate LEDs, refer to ISDN Primary Rate
Interface Maintenance (NN43001-717).
NTAK20 Clock Controller (CC) daughterboard
The NTAK20 Clock Controller daughterboard is used with the NTBK50 2.0
Mb PRI card. The NTAK79 PRI card has an onboard 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 systems, synchronization is accomplished with the
NTAK20 clock controller circuit card.
IMPORTANT!
Every Small System cabinet or Media Gateway that contains a digital trunk must
contain a clock controller. If a Small System is equipped with digital trunks, Nortel
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.
NTAK93 D-Channel Handler Interface (DCHI) daughterboard
The NTAK93 DCHI daughterboard interfaces with the system Central
Processing Unit (CPU) and mounts on the NTBK50 PRI card for PRI (but not
ISL) applications. The equivalent circuit resides onboard the NTAK79 2.0 Mb
PRI card. The DTI/PRI digital trunk card is installed in the Media Gateway.
Digital trunk cards are not supported in Media Gateway Expansions.
Copyright © 2003-2007, Nortel Networks
.
Nortel Communication Server 1000
ISDN Primary Rate Interface Installation and Commissioning
NN43001-301 02.03 Standard
Release 5.5 7 December 2007
ATTENTION