Nortel Networks Circuit Card 311 - Manual (Page 55)

Serial Data Interface (SDI) cards 55
Balancing network Depending on the card type, the balancing network is
capable of providing either a 600 ohm or a 900 ohm (or both) impedance
matching network. It also converts the 2-wire transmission path (tip and
ring) to a 4-wire transmission path (Rx/ground and Tx/ground). The
balancing network is a transformer/analog (hybrid) circuit combination.
Signaling circuits Signaling circuits are relays that place outgoing call
signaling onto the trunk. Signal detection circuits monitor the incoming
call signaling.
Control signals Control signals and logic are provided when the trunk is
going to be connected to special services such as recorded announcement
and paging equipment.
Serial Data Interface (SDI) cards
The NT8D41BA QSDI paddle board provides four bidirectional
asynchronous serial ports for the system processor, and the QPC841 QSDI
card also provides four. Any device that conforms to the RS-232-C serial
communication standard can be connected to these serial ports.
The QPC513 ESDI card provides two fully synchronous serial ports for the
system processor. The ESDI card communicates using the Link Access
Procedure Balanced (LAP-B) synchronous communication protocol.
The electrical interface uses either standard RS-232-C signals or a special
high-speed interface that combines the high-speed differential interface
of the RS-422-A standard with the handshake signals of the RS-232-C
standard.
The RS-232-C interface is normally used when data rates are less than 19.2
Kbps, and the cable length is less than 15.24 m (50 ft). The high-speed
interface is used when the signal rates are greater than 19.2 kbps (up to 64
kbps) and/or when the cable length is greater than 15.24 m (50 ft).
Table 8 "Serial data interface cards" (page 55) shows compatibility between
the three SDI cards and the various switch options.
Table 8
Serial data interface cards
Compatible System Options
Card Ports Port types 51C, 61C 81C
NT8D41BA 4 RS-232-C asynchronous X X
*See the section on the QPC513 card in this manual for details on the high-speed interface
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.