Serial (RS232) modem cable (DB9-DB25). Pinout and signals for building a Two-Wire serial (RS232) modem cable
This cable should be used for DTE to DCE (for instance computer
to modem) connections without hardware handshaking.
|
DB9 pin D-SUB female to the computer |
|
DB25 pin D-SUB male to the modem |
| |
Female |
Male |
Direction |
| Shield Ground |
|
1 |
|
| Transmit Data |
3 |
2 |
—» |
| Receive Data |
2 |
3 |
«— |
| System Ground |
5 |
7 |
|
| Jumper these: |
| Request to Send |
7 |
|
«— |
| Clear to Send |
8 |
|
«— |
| Data Set Ready |
6 |
|
«— |
| Carrier Detect |
1 |
|
«— |
| Data Terminal Ready |
4 |
|
—» |
| Request to Send |
|
4 |
—» |
| Clear to Send |
|
5 |
«— |
| Data Set Ready |
|
6 |
«— |
| Carrier Detect |
|
8 |
«— |
| Data Terminal Ready |
|
20 |
—» |
