Subject: Re: old hp345 hardware problem
To: Peter Radcliffe <>
From: Michael Wolfson <mw@costello.cnf.CORNELL.EDU>
List: port-hp300
Date: 08/15/2000 21:35:37
On Tue, 15 Aug 2000, Peter Radcliffe wrote:

> Jarkko Teppo <jate@UWasa.Fi> probably said:
> > And then again it just might work:) I seem to remember that I used the
> > same serial cable for a 345 and a 380 and it's just plain standard
> > null-modem serial cable. 
> My 9000/370 is most definately _not_ a standard 9 pin serial port.
> "Standard" 9 pin serial didn't exist when it was made, they were
> saving space on the back of the machine and supplied a breakout cable
> to 25 pin.

This is correct.  The "new" old generation of 300 series machines
(i.e. the ones with the "System Interface Board" instead of the "Human
Interface Board", like the 350, 360, and 370) used a DB9 pin for their
serial port.  The send and receive lines work fine, but all of the
handshaking lines are wrong.  The earlier "Human Interface Board" had a
DB25 with correct wiring (for the 320 and similar machines).

The new generation of 300 series machines (345, 375, 380, and 385) use
normal pinouts.  The 400 series machines use a normal pinout for the DB25,
and a breakout cable for two additional serial ports.

See for info on the
special DB9 to DB25 cable.

  -- MW