The following table shows the connections inside a standard 9 pin to 25 pin adapter.
| 9-Pin Connector | 25 Pin Connector |
| Pin 1 DCD | Pin 8 DCD |
| Pin 2 RD | Pin 3 RD |
| Pin 3 TD | Pin 2 TD |
| Pin 4 DTR | Pin 20 DTR |
| Pin 5 GND | Pin 7 GND |
| Pin 6 DSR | Pin 6 DSR |
| Pin 7 RTS | Pin 4 RTS |
| Pin 8 CTS | Pin 5 CTS |
| Pin 9 RI | Pin 22 RI |