Date   : Thu, 28 Jul 2005 13:32:34 +0100 (BST)
From   : Greg Cook <debounce@...>
Subject: Re: Null Modem Cable

On Wed, 27 Jul 2005 23:46:37 +0100 (BST), Pete Turnbull
<pete@...> wrote:

> On Jul 27 2005, 19:23, Greg Cook wrote:
[snip] 
> > As much as Acorn wanted to offer null modem and straight-through
> > connection with one cable, they had to prevent two line drivers
> being
> > connected together.  As it stands, the outputs connect to inputs
> > whichever way round the plug is inserted.
> 
> I don't believe that's the reason.  You won't normally damage RS423
> line drivers by connecting two together.  When I was at Acorn I was
> told that it was intended to use the domino plug wired diagonally to
> allow for reversing the signals, but it was laid out incorrectly and
> there wasn't time to change it.

Yowch!  Fingers duly burnt.  Last time I speculate on this list,
promise!

It was mentioned Acorn had a choice about the DIN plugs.  IIRC there
have been 9 DIN connectors in the standard shell (pins/angle):
3/180, 4/216, 5/180, 5/240, 1+5/240, 7/270, 1+7/270, 3+5/180,
13/rectangular array.  

Greg



               
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