Nortel Networks Circuit Card 311 - Manual (Page 804)

804 NT8D41AA Serial Data Interface Paddle Board
paddle board block diagram" (page 804) . 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 263
NT8D41AA SDI paddle board block diagram
System considerations
In dual-processor 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 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 the maintenance
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.