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57
MODULAR SMART SWITCH
A.4 Connecting to Modems
The cable shown in Figure A-4 can be used to connect to most standard
modems. Do not connect additional lines.
Figure A-4. Cable Pinout for Modems.
Modular Smart Switch end
25-Pin socket connector
Printer end
25-pin plug connector
1
2
3
4
5
7
20
1
2
3
4
5
7
20
56
MODULAR SMART SWITCH
Figure A-2. IBM AT Serial Cable Pinning.
A.3 Connecting to Printers
Most serial printers provide a standard DB25 connector for serial data. The
required cable wiring is shown in Figure A-3. This wiring configuration is
suitable for many popular printers such as HP
®
LaserJet
®
, QMS, Brother
®
,
and Epson
®
(with serial-port card).
Figure A-3. Cable Pinout for Serial Printers.
2
3
5
6
20
7
Modular Smart Switch end
25-Pin socket connector
TXD
RXD
CTS
DTR
GND
3
2
20
5
6
7
Printer end
25-pin plug connector
2
3
5
6
8
IBM AT end
9-Pin socket connector
2
3
7
20
5
Modular Smart Switch end
25-Pin socket connector
TXD
RXD
GND
DTR
CTS
4
Modem end
25-pin plug connector