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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 or trunk 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/trunk card, initializes it, and puts it into an operational mode.
The network card regularly polls the IPE cards during TS0 to see if any
of them has a message to be sent. When an IPE card has a message
waiting it responds to the poll by sending a series of 1s during the next five
successive timeslot 0s. The network card responds by sending a "message
send enable" message (all 1s). The IPE card replies by sending 1, 1, 1, 0,
and then the message in successive timeslot 0s.
Trunk interface unit
Once the 8-bit digital voice signal has been received by the trunk card, it
must be converted back into an analog signal, filtered, and driven onto the
analog trunk line through an impedance matching and balance network.
The trunk interface also includes the logic necessary to place outgoing call
signaling onto the trunk, or the logic to connect to special services such as
recorded announcement and paging equipment.
Figure 14 "Typical trunk interface unit block diagram" (page 54)
typical example of the logic that performs these functions. Each part of the
trunk interface unit is discussed in the following section.
Copyright © 2003-2008, Nortel Networks
.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Operation 53
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