Nortel Networks 1000 - Manual (Page 53)

Operation 53
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 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 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) shows a
typical example of the logic that performs these functions. Each part of the
trunk interface unit is discussed in the following section.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.