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Re: serial mouse on older pmac?

On  14 Aug, this message from Brian Hicks echoed through cyberspace:
> On Tue, Aug 14, 2001 at 10:39:03AM +0200, furball@space.ch wrote:
>> Does anyone ever have tried this? Does anyone know if
>> the mouse requires a PC serial port (rs232) or if it
>> works on macs (rs???) as well? are the drivers for
>> gpm and (most importantly) X compiled-in (or left out
>> due to "improbable config")?
> Well, mac serial ports are rs232, just a different connector.

Nope. Macs use RS422, which is different from RS232 in various ways:

- different handshake signals
- differential signals vs. single-ended (ground-referenced) signals for
- RS232 specifies DB25 connector, DB9 also widely used; RS422 doesn't
  specify connector. Macs have always used 8-pin mimi-DIN.

RS422 can be adapted to RS232 through a hack (that's really what it
is...), by connecting TX- on the Mac to TX on the RS232 input, the Mac's
RX- to RX on the RS232, and the Mac's RX+ to GND (important).


Michel Lanners                 |  " Read Philosophy.  Study Art.
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email   mlan@cpu.lu            |
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