fission  (fission@mb.sympatico.ca) wrote:

Here's a more complete answer than the one I e-mailed to you.

>I have a new (okay, old) terminal that I would like to use with my
>powermac running NetBSD/macppc.  The only problem is that my serial port
>on a Macintosh is a DB8 (I think that's what it's called, anyways -
>whatever Mac serial ports use) and the terminal has a 25-pin serial port.
>Any idea on how to make a cable that would convert between the two?
>

If I remember correctly there are a couple of ways to do this with 
off-the-shelf cables and adapters.  You can use a standard Mac Modem 
cable and a Gender Changer, or you can use an ImageWriter I cable and a 
Null modem.    The Mac modem cable is a DIN-8 to DB-25 male with the 
Rx/Tx lead reversed, so the Gender Changer will correct the sex on the 
DB-25 end.  The ImageWriter I cable is a DIN-8 to DB-25 female with the 
Rx/Tx leads wired straight thru, so you'll need a DB-25 Null Modem to get 
the right sex on the DB-25 end.

Watch out for the configuration of the Mac modem cable; there were at 
least three different configurations sold at various times.  Get one that 
is labeled "Hi-speed" as it will have the proper orientation of RTS/CTS 
for the Mac.

(Don't confuse an ImageWriter I cable with an ImageWriter II cable.  The 
ImageWriter II is the equivalent of a Mac modem cable with a DIN-8 on 
each end.  It can be used to connect two Macs together via their serial 
ports.)

>Even if I could get two diagrams (one for the Mac cable and one for 25-pin
>serial cable) I could probably figure out how to make it work.  Any URLs
>for images/ASCII diagrams would just make my day.  =)

If you're handy with a soldering iron, have a steady hand and good 
eyesight or a darned good magnifying glass you can make your own cables.  
I have the wiring diagrams posted at:

  http://murphy.dyndns.org/NetBSD/cables.html

If you want full flow control make sure you wire CTS/RTS and don't tie 
them to DTR.

-bob