| DB9 (socket) | DB25 (plug) | Signal |
| 1 | 8 | DCD |
| 2 | 3 | RxD |
| 3 | 2 | TxD |
| 4 | 20 | DTR |
| 5 | 7 | SG |
| 6 | 6 | DSR |
| 7 | 4 | RTS |
| 8 | 5 | CTS |
| 9 | 22 | R1 |
| Shell | Shell | Shield |
| Mac Din 8 | PC DB 9 | ||
| Pin | Signal | Pin | Signal |
| 1 | DTR | 1 | DCD |
| 2 | DSR | 2 | RxD |
| 3 | TxD- | 3 | TxD |
| 4 | SG | 4 | DTR |
| 5 | RxD- | 5 | SG |
| 6 | TxD- | 6 | DSR |
| 7 | DCD | 7 | RTS |
| 8 | RxD+ | 8 | CTS |
| - | - | 9 | RI |