This connector is not present on Macintosh 128K, 512K, and 512K enhanced computers. To connect DE-9 cables to the Mini DIN-8 port, use adapter cable 590-0341 (beige) or 590-0553/699-0430 (smoke).. a. On serial port A (modem), if the VIA1 SYNC signal is high, this input will be routed to the receive/transmit clock input of the SCC. This clock input supports high-speed synchronous devices. Pin 7 is not connected on the Macintosh Plus, LC, or IIsi.
8 pin Apple mini din connector at the end of the peripheral cable, from the front of the connector
| Pin | Signal | Description |
| 1 | HSKo | Handshake out |
| 2 | HSKi | Handshake in/external clock |
| 3 | TxD- | Transmit data - |
| 4 | GND | Signal ground |
| 5 | RxD- | Receive data - |
| 6 | TxD+ | Transmit data + |
| 7 | GPI/NC | General-purpose input or no connection |
| 8 | RxD+ | Receive data + |