Serial (RS232) modem cable (2-wire, DB25-DB25)
This cable should be used for DTE to DCE (for instance, from computer to a modem) connections without hardware handshaking.
|  | DB25 pin D-SUB female to the PC | 
|  | DB25 pin D-SUB male to the modem | 
| Female | Male | Direction | |
|---|---|---|---|
| Shield Ground | 1 | 1 | |
| Transmit Data | 2 | 2 | → | 
| Receive Data | 3 | 3 | ← | 
| System Ground | 7 | 7 | |
| Jumper these: | |||
| Request to Send | 4 | → | |
| Clear to Send | 5 | ← | |
| Data Set Ready | 6 | ← | |
| Carrier Detect | 8 | ← | |
| Data Terminal Ready | 20 | → | |
| Request to Send | 4 | → | |
| Clear to Send | 5 | ← | |
| Data Set Ready | 6 | ← | |
| Carrier Detect | 8 | ← | |
| Data Terminal Ready | 20 | → | |
RS232 modem cable (2-wire, DB9-DB25)
Modem cable (2-wire, DB25-DB25)
Full mode modem cable (DB9-DB25)
Complete modem cable (DB25-DB25)