> Different question: I saw a previous post about the Mac's different
> serial ports ( as opposed to a PC).  I'm planning on implementing a
> BBS system on NetBSD (via Perl), and I'm going to need my modem to
> clear the line on carrier or terminal drop.  Aside from configuration
> problems, are there any special concerns I should know about?

Not that I'm aware of (other than the traditional muddle of RS232
problems). The thing is that the Mac only has one output pin, whereas
PC's (and standard RS232) have at least two. The two most useful ones
are RTS (send me data please) and DTR (I'm ready). DTR is commonly used
to enable modems; mine will drop carrier if DTR goes off.

So we have one pin for two functions; the question is which will it
do? Most modem cables today (sample size of 3 cables) have the output
hooked up to DTR, which is how NetBSD/mac wants it.

Printer or computer-to-computer connections are different; there the more
important thing to do is make the other computer shut up. In that
case, this output needs to be wired up as RTS. The DeskWriter printer
cables do this automagically.

I haven't documented it yet, but the current tty drivers are set up to
be able to generate either configuration (they can use the output for
either function). If you stty -f /dev/tty0X crtscts , then
you get the output acting as DTR. This mode is fine for either
dealing with a modem or driving a DeskWriter (the handshaking input
line, the line telling the Mac to shut up, is always connected).
If, however, you do stty -f /dev/tty0X crtscts mdmbuf (enable BOTH
forms of handshaking), then the drivers are suypposed to use
the output for asking the other computer to please hush.

This latter feature has not been tested yet; I'm still trying to get
my SE/30 to boot w/ NetBSD (more in next post). Once it's done, I'll
test this mode out. Though it's based on code from the sun3 driver, which
does work.

Take care,

Bill