This 9-pin port should be the same for a standard PC serial port, the GVP IO Extender, ASDG Dual Serial, and the MultiFace II,III,IV.
| PC 9 Pin Connector | Signal | Amiga DB25 Connector | 1 | DCD | 8 | 2 | RxD | 3 | 3 | TxD | 2 | 4 | DTR | 20 | 5 | GND | 7 | 6 | DSR | 6 | 7 | RTS | 4 | 8 | CTS | 5 | 9 | RI | 22 | * Taken from the ASDG Dual Serial Card Manual
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