Nortel NT1R20 Description page 46

Page 22 of 290 Description
553-3001-105 Standard 5.00 June 1999
A card LAN link bus is common to all of the line/trunk card slots within an
IPE module (or IPE section of a CE/PE module). This bus is arranged in a
master/slave configuration where the controller card is the master and all
other cards are slaves. The module backplane provides each line/trunk card
slot with a unique hardwired slot address. This slot address enables a slave
card to respond when addressed by the controller card. The controller card
communicates with only one slave at a time.
In normal operation, the controller card continually scans (polls) all of the
slave cards connected to the card LAN to monitor their presence and
operational status. The slave card sends replies to the controller on the input
bus along with its card slot address for identification. In this reply, the slave
informs the controller if any change in card status has taken place. The
controller can then prompt the slave for specific information. Slaves only
respond when prompted by the controller; they do not initiate exchange of
control or status data on their own.
When an IPE line card is first plugged into the backplane, it runs a self-test.
When the self-test is completed, a properly functioning card responds to the
next controller card poll with the self-test status. The controller then queries
for card identification and other status information. The controller then
downloads all applicable configuration data to the line card, initializes it, and
puts it into an operational mode.