Nortel Networks Circuit Card 311 - Manual (Page 813)

Functional description 813
paddle board block diagram" (page 813) . Other logic on the card includes
two baud rate generators, two RS-232-C driver/receiver pairs, and the
switches and logic needed to configure the UARTs.
Figure 267
NT8D41AA SDI paddle board block diagram
System considerations
In dual-processor Meridian 1 systems, the SDI paddle board behaves
differently depending on which backplane socket it is installed in. Installing
the paddle board into a socket in the network area of the backplane allows
it to work when either of the system processors is active. Installing the
paddle board into a socket in the CPU area of the backplane allows it to
work only when that CPU is active.
The SDI paddle board is normally installed into a socket in the network
area of the backplane. This allows it to be accessed by either of the
system processors. This is necessary because the active CPU switches
automatically each night at midnight, and whenever a fault occurs on the
active CPU card.
The SDI paddle board can also be installed into a socket in the CPU area of
the backplane. This is done when performing maintenance or an upgrade
on the Meridian 1 system. The SDI paddle board is plugged into the CPU
that is not the active system CPU. One of the serial ports on the SDI
paddle board is then connected to a maintenance terminal and the CPU
board is put into maintenance mode. Diagnostics can then be run from
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
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