Macintosh RS-422

From HwB

It's possible to connect RS-232 peripheral to the RS-422 port available on Macintosh computers. Use RXD- as RXD, TXD- as TXD, Ground RXD+, Leave TXD+ unconnected, GPi as CD.



8 PIN MINI-DIN FEMALE at the computer.

Pin Name Dir Description
1 HSKo Arrowr.png Output Handshake
2 HSKi/CLK Arrowl.png Input Handshake or External Clock
3 TXD- Arrowr.png Transmit Data (-)
4 GND Arrow.png Ground
5 RXD- Arrowl.png Receive Data (-)
6 TXD+ Arrowr.png Transmit Data (+)
7 GPi Arrowl.png General Purpose Input
8 RXD+ Arrowl.png Receive Data (+)

Note: Direction is DTE (Computer) relative DCE (Modem).

Note: GPi is connected to SCC Data Carrier Detect (or to Receive/Transmit Clock if the VIA1 SYNC signal is high). Not connected on the Macintosh Plus, Classic, Classic II, LC, LC II or IIsi.