串行直連電纜用于兩臺臺電腦通過串行口直接相連，電纜兩端的插頭都是9 針的母插頭：
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兩臺電腦串行通信直連對接方法引腳定義 |
通過此表可以看出兩臺電腦通過串口直接連接傳輸數據的接線方法：
|
|
D-Sub 1 |
D-Sub 2 |
|
|---|---|---|---|
|
Receive Data |
2 |
3 |
Transmit Data |
|
Transmit Data |
3 |
2 |
Receive Data |
|
Data Terminal Ready |
4 |
6+1 |
Data Set Ready + Carrier Detect |
|
System Ground |
5 |
5 |
System Ground |
|
Data Set Ready + Carrier Detect |
6+1 |
4 |
Data Terminal Ready |
|
Request to Send |
7 |
8 |
Clear to Send |
|
Clear to Send |
8 |
7 |
Request to Send |