mac serial pinouts

From: Mark Tapley <mtapley_at_swri.edu>
Date: Mon Oct 9 17:22:43 2000

Larry Walker wrote:

> I've also got a NEXT which IIRC uses RS423 prot. but has a
>similiar miniDIN. These guys really keep the cable manufacturers
>busy. Again the specs are hard to find. Is there such a thing as a
>repositry of cable connection specs ?

Ooooh ooooh! I can help! A quick cut, paste, ftp, and addition of a little
ascii art later, here, almost straight from the on-line copy of the System
Admin's manual on my NeXT running NeXTStep 3.3 are:

NeXT Computer Serial Ports

Serial ports A and B use 8-pin miniature DIN (MiniDIN-8) connectors. Both
ports on a 68040-based NeXT computer are RS-423 compatible; the ports on a
68030-based NeXT computer are RS-422 compatible (though different). The
following diagram and table describe the pin configuration of each port:

         8 7 6
        5 4 3
          2 1 (ed. drawing makes each location look like a
                        socket, not a pin, as would be found on the
                        back side of the computer. That matches my '040 Cube.)

Pin Signal Pin Signal
        1 DTR 5 RXD
        2 DCD 6 RTS
        3 TXD 7 RTXC
        4 GND 8 CTS


NeXT-to-Modem Cable (MiniDIN-8 to DB-25)

The following table describes the configuration of a cable used to connect
a 68040-based NeXT computer to an asynchronous modem. This configuration
supports RTS/CTS hardware flow control.

MiniDIN-8 DB-25
Pin Signal Pin Signal
1 DTR 20 DTR
2 DCD 8 DCD
3 TXD 2 TXD
4 GND 7 GND
5 RXD 3 RXD
6 RTS 4 RTS
7 (Not connected)
8 CTS 5 CTS


NeXT Null-Modem Cable (MiniDIN-8 to DB-25)

The following table describes the configuration of a null-modem style cable
used to connect a terminal, printer, or other computer to a NeXT computer.
This configuration supports RTS/CTS hardware flow control.

MiniDIN-8 RS-232
Pin Signal Pin Signal
1 DTR 8 DCD
2 DCD 20 DTR
3 TXD 3 RXD
4 GND 7 GND
5 RXD 2 TXD
6 RTS 5 CTS
7 (Not connected)
8 CTS 4 RTS


NeXT Null-Modem Cable (MiniDIN-8 to MiniDIN-8)

The following table describes the configuration of a null-modem style cable
used to connect two 68040-based NeXT computers. This configuration supports
RTS/CTS hardware flow control.

MiniDIN-8 MiniDIN-8
Pin Signal Pin Signal
1 DTR 2 DCD
2 DCD 1 DTR
3 TXD 5 RXD
4 GND 4 GND
5 RXD 3 TXD
6 RTS 8 CTS
7 (Not connected)
8 CTS 6 RTS

NeXT Null-Modem Cable (DTR Flow Control)

The following table describes the configuration of a null-modem cable used
to connect a NeXT computer to a printer that only supports DTR hardware
flow control, rather than RTS/CTS hardware flow control.

MiniDIN-8 RS-232
Pin Signal Pin Signal
1 DTR 8 DCD
2 DCD 5 CTS
3 TXD 3 RXD
4 GND 7 GND
5 RXD 2 TXD
6 RTS 20 DTR
7 (Not connected)
8 CTS 4 RTS


Heck of a time to ask, but NeXTs are on-topic now right? Right? I hope? The
copyright on the back of my box says (c)1989.
                                                                - Mark
Received on Mon Oct 09 2000 - 17:22:43 BST