Date   : Mon, 30 Mar 2009 10:47:12 +0100
From   : pete@... (Pete Turnbull)
Subject: A few Econet questions

On 30/03/2009 09:58, Phil Blundell wrote:
> On Sun, 2009-03-29 at 23:57 +0100, Pete Turnbull wrote:
>> If this is what I think it is, it's the collision detect IC, the inputs 
>> of which are connected to the data+ and data- lines.  Not fitted on some 
>> variants of the board, because after selling lots of modules with the 
>> collison detect, some bright spark in Acorn figured out that the 
>> software took care of it anyway, and the hardware wasn't needed.
> 
> I thought the business with removing and then reinstating the
> collision-detect circuitry happened much earlier; my recollection was
> that, having been included in the Beeb interface circuit, it was left
> out of the first version of the Master plug-in module but then later
> added back on for the reasons you mentioned.

That's correct, but who knows what Acorn may have got up to with 
ARM-based machines ;-)  Someone mentioned a surface-mount device; I've 
not been able to look closely enough at the photo but it's possible that 
there was an option for either SMT or DIL on the board.

-- 

Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York