Subject: Re: >Various ramblings...
To: Marc St-Jean <>
From: Bill Studenmund <>
List: macbsd-general
Date: 08/30/1995 17:02:10
(Sorry if people get 2 copies. I'm trying to help w/ the switch to
> RE>>Various ramblings...
> >I'm almost certain that Macs can't do both hardware handshaking and
> >disconnect detect at the same time. The problem is that the DIN8 serial
> >connector they use doesn't have enough pins for all of the traditional
> >RS232 signals. Specifically, it has DTR and CTS, but it doesn't have DCD,
> >DSR or RTS.  (Two of the pins are used for RS422 differential transmission
> >and just map to ground on RS232.)
> >
> >Most of this is from memory, so I could be wrong.  Does anyone out there 
> >have conflicting information?  (I've copied this to the list so others
> >can jump in.)
> >From what I understand it can do disconnect detect but not hardware hangup.
> Macs since the SE (I think) have DCS.  The problem is that DTR must be used
> for RTS, so you can't do DTR hangup.

True. I've been hacking on the serial driver to try and get my DeskWriter
to work properly (I've got ghostscript ready to go once I do). The mac
serial port can do hardware flow control on both input and output (I'm
pretty sure on the input; certain on the output control). It can also
do disconnect detect. It can not do hardware hangup.

The real problem at present is that the current version of ser.c is the
version used to get MacBSD up and running. It was good enough to work
and help people out with terminals when the ADB system didn't work.
It's just that now we've progressed to the point where we want a more-
robust system. We want 57600 transmission (both ways if possible) and
hardware flow control enabled (it doen't work at present; crtscts is
totally ignored).

I've been trying to solve some of these problems. I'm about half-way
there. I think there's hope, but it's in the two to three week time

Take care,