| Pin DE9 | Pin DB25 | Signal | In/Out | Description |
|---|---|---|---|---|
| 1 | 8 | DCD | In | Data Carrier Detect |
| 2 | 3 | RXD | In | Receive Data |
| 3 | 2 | TXD | Out | Transmit Data |
| 4 | 20 | DTR | Out | Data Terminal Ready |
| 5 | 7 | GND | - | Ground |
| 6 | 6 | DSR | In | Data Set Ready |
| 7 | 4 | RTS | Out | Request To Send |
| 8 | 5 | CTS | In | Clear To Send |
| 9 | 22 | -RI | In | Ring Indicator |
| Connector 1 | Connector 2 |
|---|---|
| TxD | RxD |
| RxD | TxD |
| RTS | CTS |
| CTS | RTS |
| SG | SG |
| DSR | DTR |
| DCD | |
| DTR | DSR |
| DCD |