Db25 serial cables and loopback plugs, Db25 signals, Db25 null-modem cables – Comtrol RocketPort Plus Universal PCI User Manual
Page 12: Db25 signals db25 null-modem cables
12 - Connecting Serial Devices
RocketPort Plus Universal PCI User Guide: 2000369 Rev. C
Connecting Serial Devices
DB25 Serial Cables and Loopback Plugs
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The following figures and table illustrate the signals present on DB25
connectors if you need to build your own null-modem or straight-through
serial cables. Refer to the manufacturer’s installation guide if you need help
with connector pinouts or cables for the peripheral device.
•
•
DB25 Straight-Through Cables (RS-232)
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DB25 Signals
This subsection provides DB25 signal information. Refer to
the manufacturer’s installation documentation if you need
help with the connector pinouts or cabling for the serial
device.
This table shows connector information for DB25
connectors.
DB25 Null-Modem
Cables
You need a null-modem cable to connect to DTE devices. For example, you can
connect one end of a a null-modem cable to COM2 on one computer and the other
end of the null-modem cable to COM2 on another computer.
Quad/Octacable
Pin
RS-232 Signal
1
Not used
2
TxD
3
RxD
4
RTS
5
CTS
6
DSR
7
Signal ground
8
DCD
9 to 14
Not used
15
Not used
16
Not used
17
Not used
18
Not used
19
Not used
20
DTR
21
Not used
22
RI
23-24
Not used
25
Not used
Pin 14
Pin 25
Pin 1
Pin 13
DB25 Male