In article ,
Andy Champ writes:
On 29/03/2013 23:58, bm wrote:
+1
In 48 years I've never needed one. If I can't fix it with a DMM/AVO, scope,
logic analyser etc it either 'aint worth fixing or I'm incapable. Maybe it
depends on the type of kit you're playing with. Same as TDRs, never needed
to use one.

I've never had a TDR, but several times wished I did. It would have been
really nice in the days of thinnet to be able to press a button and get
an idea of which plonker had undone the t-piece, and if that wasn't
enough to binary chop until I had him.

Likewise.
I wrote the ethernet driver for a minicomputer many decades ago.
When I got the jammed flag set (implying a shorted or open circuit
cable generating reflections on every transmit attempt), I reported
the internal TDR value recorded by the AMD LANCE chipset. It somewhat
surprises me that no other ethernet driver I ever saw reported this
most useful information. The resolution wasn't great, but it was
loads better than having nothing. Several customers told me that
when their company ethernet went down, they'd go over to the console
of their GEC4000 and look to see how far the cable fault was from it.

Luckily I've never been full time networks

Andy

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Andrew Gabriel
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