On Sun, 25 Oct 1998, Johan Carlsson wrote:

> On Thu, 22 Oct 1998, Dr. Bill Studenmund wrote:
> 
> Hi Dr. Bill! I was hoping you would chime in ;-)
> 
> > On Wed, 21 Oct 1998, Johan Carlsson wrote:
> 
> [snip]
> 
> > > So, I'm trying to connect a FreeBSD PC (acheron) w/ a NetBSD IIsi (spock)
> > > w/ a null-modem cable from PC COM2 to the Mac modem port. FreeBSD 2.7.2
> > > (homebrewed kernel but I haven't messed w/ sio1 or ppp0) and NetBSD/mac68k
> > > 1.3.2 GENERICIWMSBC#5, respectively.
> > [snip]
> > 
> > Don't stick modem in there. You don't have a modem, and it'll only make
> > life harder.
> 
> OK (I've reread the cdtrcts part of pppd(8) more carefully now).
> Unfortunately *the FreeBSD pppd doesn't have a cdtrcts option* so after
> editing /etc/syslog.conf (thanks Frederick!) I fired up pppd on the PC:

You don't need cdtrcts for the freebsd side. The null modem I described
maps the i386's (RTS, CTS) to the amc68k's (CTS, DTR). So the mac needs
cdtrcts, and the pc crtscts.

I doubt you need hardware handshaking for the IIsi at 9600 baud.

> acheron # pppd cuaa1 9600 debug kdebug 7 nocrtscts local silent
> 
> And then on the IIsi:
> 
> spock # pppd tty00 9600 debug kdebug 7 nocrtscts local

Put one of them in passive mode. Otherwise you have to get the timing just
right. I'm not sure how long it takes to timeout the transmissions, but
it'll just be a pain w/o one side (the first one you fire up) being in
passive mode.

[snip]

I'm not sure how silent mode differes from passive, but I've gotten
passive to work before, so I know it works. :-)

> This is w/ a null modem wired after Dr. Bill's instructions (and checked
> w/ a multimeter). Again I tried all the pppd options I could think of:
> xonxoff, nomagic, even cdtrcts on the Mac and nocrtscts on the PC, but the
> result was virtually the same as in the above cases (only the contents of
> the packets sent differed).

Can the two machines talk to each other using terminal emulating softare?

> > Assuming this is 1.3.2, don't use crtscts, use cdtrcts. Then you'll turn
> > on full hardware handshaking (the mac serial port doesn't have an RTS pin,
> > just CTS, DTR, and DCD).
> 
> Do you mean crtscts could work w/ -current? If not I'd be willing to try
> to port the NetBSD pppd to FreeBSD in order to get the cdtrcts option.
> Alternatively, would it help building a null modem specifically for use w/
> the nocrtscts and local options? TIA (I really appreciate your help),

The null modem you have should be fine.

cdtrcts, though supported in pppd, is really a function of the driver.
Only NetBSD serial drivers (and right now only the mac68k serial drivers)
support it - it'd do no good on FreeBSD.

Under -current (and 1.3.2), crtscts tells the computer to only send data
when CTS is asserted, but to not bother trying to stop the other side's
transmission. This mode is great for talking to my DeskWriter, and my
modem. It leves DTR open as a modem control line, and it'll stop output 
when the modem gets full (since I talk to my modem at a rate faster than
the modem sends to the other side).

Take care,

Bill