| Nullmodem Cable 9pin D-Sub to 9pin D-Sub | |||
| D-Sub 1, female | D-Sub 2, female | ||
| 2 | Receive Data | 3 | Transmit Data |
| 3 | Transmit Data | 2 | Receive Data |
| 4 | Data Terminal Ready | 6+1 | Data Set Ready + Carrier Detect |
| 5 | System Ground | 5 | System Ground |
| 6+1 | Data Set Ready + Carrier Detect | 4 | Data Terminal Ready |
| 7 | Request to Send | 8 | Clear to Send |
| 8 | Clear to Send | 7 | Request to Send |
| Nullmodem Cable 25pin D-Sub to 25pin D-Sub | |||
| D-Sub 1, female | D-Sub 2, female | ||
| 2 | Transmit Data | 3 | Receive Data |
| 3 | Receive Data | 2 | Transmit Data |
| 4 | Request to Send | 5 | Clear to Send |
| 5 | Clear to Send | 4 | Request to Send |
| 6+8 | Data Set Ready + Carrier Detect | 20 | Data Terminal Ready |
| 7 | GND | 7 | GND |
| 20 | Data Terminal Ready | 6+8 | Data Set Ready + Carrier Detect |
