Ntak20 Clock Controller (Cc) Daughterboard; Ntak93 D-Channel Handler Interface (Dchi) Daughterboard - Nortel Meridian 1 Administration And Maintenance

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NTAK20 Clock Controller (CC) daughterboard

NTAK93 D-Channel Handler Interface (DCHI) daughterboard

553-3011-311 Standard 7.0
Appendix A — 2Mb 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 more information on the operation of the clock controller, refer to the
chapter in this guide called "Network clocking".
The NTAK20 Clock Controller daughterboard is used with the NTBK50 2.0
Mb PRI card. (The NTAK79 PRI card has an on-board clock controller).
Digital Trunking requires synchronized clocking so that a shift in one clock
source will result in an equivalent shift of the same size and direction in all
parts of the network. On Option 11 systems, synchronization is accomplished
with the NTAK20 clock controller circuit card.
The Clock Controller circuitry synchronizes the Option 11 to an external
reference clock, and generates and distributes the clock to the system. Option
11 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. See the chapter called Network clocking for
details.
The NTAK93 DCHI daughterboard interfaces with the Meridian 1 Option 11
Central Processing Unit (CPU) and mounts on the NTBK50 PRI card for PRI
(but not ISL) applications. The equivalent circuit is contained on-board the
NTAK79 2.0 Mb PRI card.
The DCHI is responsible for performing the Q.921 layer 2 protocol
information. It transfers layer 3 signaling information between two adjacent
network switches.
The NTAK93 DCH daughterboard, when installed on the NTBK50 circuit
card, is addressed in the same slot as the NTBK50. The NTAK93 can use SDI
I/O addresses 0 to 15 and port 1.
May 1999