Use this cable between two DTE devices (for instance two laptops).
 |
RS232 port pinout on Side 1 |
|
RS232 port pinout on Side 2 |
| DB9-1 | DB9-2 | ||
|---|---|---|---|
| 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 |
Use this cable between two devices: DTE and DCE (for example, a computer and a printer).
| DB9 | DB25 | ||
|---|---|---|---|
| Receive Data | 3 | 3 | Transmit Data |
| Transmit Data | 2 | 2 | Receive Data |
| Clear To Send + Data Set Ready | 8 + 6 | 20 | Data Terminal Ready |
| Carrier Detect + Data Terminal Ready | 1 + 4 | ||
| Ground | 5 | 7 | Ground |
– If your devices have other connectors (for example, DB-25 pin) look here: RS-232 – RS-232 connection using DB25 connectors.
– RS232 port connector with all pins.