9 pin DE9 male connector at the computer.
10 pin IDC male connector at
motherboard.
| DE9 Pin | IDC 10 Pin | Name | Dir | Description |
|---|---|---|---|---|
| 1 | 1 | CD | IN | Carrier Detect |
| 2 | 3 | RXD | IN | Receive Data |
| 3 | 5 | TXD | OUT | Transmit Data |
| 4 | 7 | DTR | OUT | Data Terminal Ready |
| 5 | 9 | GND | - | System Ground |
| 6 | 2 | DSR | IN | Data Set Ready |
| 7 | 4 | RTS | OUT | Request to Send |
| 8 | 6 | CTS | IN | Clear to Send |
| 9 | 8 | RI | IN | Ring Indicator |
Notes
- Direction is DTE (Computer) relative DCE (Modem)