Chapter 1
Motherboard Description
Connectivity
The serial ports can be used in many ways, and it may be necessary to become
familiar with the pinout diagram. The following chart gives you the function of
each pin on the 9-pin connector and some of the 25-pin connector. This
information can be used when configuring certain software programs to work with
the serial ports.
Signal
Name
DB9 PIN
DB25 PIN
DCD
Data Carrier Detect
1
8
RX
Receive Data
2
3
TX
Transmit Data
3
2
DTR
Data Terminal Ready
4
20
GND
Signal Ground
5
7
DSR
Data Set Ready
6
6
RTS
Request to Send
7
4
CTS
Clear to Send
8
5
RI
Ring Indicator
9
22
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