Re: Connecting 2 e450s via serial port (fairly newbie-ish question)

From: Dr. David Kirkby (drkirkby_at_ntlworld.com)
Date: 07/29/03 

Date: Tue, 29 Jul 2003 16:50:04 +0100

Ben wrote:
>
> Hi all. I'd like to connect 2 e450s via a serial connection so I can
> tip from one to the other. I am doing some testing which will require
> 1 of the 450s to be in single user mode and I will be remote.
>
> I have tried connecting the 2 A/B ports with a null modem cable and
> tip-ing to cua/a but that didn't get me anywhere. Can anyone else give
> me a tip or 2?
>
> Thanks.
The machine you want to run in single user mode needs a connection on
port A. You need to connect at 9600 8N1. The other machine does not
matter. Use A or B or that.

I built such a cable from information at
http://www.obsolyte.com/sunFAQ/serial/
The 25-25 pin cable they suggest does indeed work. Apparently, not all
null modem cables have all the connections, so that might be your
problem.

Note, I'm sure there is an error in the pinouts at that site for the
9->25 pin cable. Pins 2 and 3 should be crossed. (I'm also sure I
pointed this out to them, but it does not seem to have changed.)
Perhaps someone else might confirm my suspicions that the following is
wrong:

25 pin 9 pin
pin 1 GND - pin 1 GND
pin 2 TXD - pin 3 RXD
pin 3 RXD - pin 3 TXD
pin 4 RTS - pin 8 CTS
pin 5 CTS - pin 7 RTS
pin 7 gnd - pin 5 gnd
pin 6 DSR - pin 4 DTR
pin 20 DTR - pin 6 DSR

I tip to 'hardwarea', where /etc/remote has the line:

hardwirea:\
        :dv=/dev/term/a:br#9600:el=^C^S^Q^U^D:ie=%$:oe=^D:
(I think spaces/tabs) might be important, so copy the 'hardwire' line,
then substitute b for a. Don't cut and past the line I've put here.

One thing to note, to exit tip, use a tilda (~) followed by a full
stop.

Hope that is of some help. 

-- 
Dr. David Kirkby,
Senior Research Fellow,
Department of Medical Physics,
University College London,
11-20 Capper St, London, WC1E 6JA.
Tel: 020 7679 6408 Fax: 020 7679 6269
Internal telephone: ext 46408
e-mail davek@medphys.ucl.ac.uk