Nortel Networks Video Gaming Accessories 553-3001-211 Manual De Usuario

 Overview

A card LAN link bus is common to all of the line/trunk card slots within an 
IPE 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 its 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.

Once the 8-bit digital voice signal has been received by the analog line card, 
it must be converted back into an analog signal, filtered, converted from a 
4-wire transmission path to a 2-wire transmission path, and driven onto the 
analog telephone line. 

 shows a typical example of the logic that performs these 

functions. Each part of the analog line interface unit is discussed in the 
following section.