9 pin Apple mini din
connector at the end of the peripheral cable, from the front of the
connector.
The back panel of all Power Macintosh models contain two I/O ports for serial telecommunication data.
GeoPort was a serial data system used on some models of the Apple Macintosh. GeoPort modified the “meaning” of the existing Mac serial port pins to add a new high-speed DMA channel that allowed the Mac"s internal sound hardware to emulate various devices such as modems and fax machines. GeoPort could be found on late-model m68k-based machines (the AV series) as well as all pre-USB Power Macintosh models.
| Pin | Signal | Description |
|---|---|---|
| 1 | SCLK (out) | Reset pod or get pod attention |
| 2 | Sync (in)/SCLK (in) | Serial clock from pod (up to 920 Kbit/sec.) |
| 3 | TxD- | Transmit - |
| 4 | Gnd/shield | Ground |
| 5 | RxD- | Receive - |
| 6 | TxD+ | Transmit + |
| 7 | Wake up/TxHS | Wake up CPU or do DMA handshake |
| 8 | RxD+ | Receive + |
| 9 | +5V | Power to pod (350 mA maximum) |