The back panel of all Power Macintosh models contain two I/O ports for serial telecommunication data. Both sockets accept 9-pin plugs, allowing either port to be independently programmed for asynchronous or synchronous communication formats up to 9600 bps. This includes
AppleTalk and the full range of Apple
GeoPort protocols.
9 pin Apple mini din connector at the end of the peripheral cable, from the front of the connector
Pin | Signal | Description |
1 | SCLK (out) | Reset pod or get pod attention |
2 | SCLK (in) | Serial clock from pod (up to 920 Kbit/sec.) |
3 | TxD- | Transmit - |
4 | GND | 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) |