[ltp] 100mbit only when docked?

James Knott linux-thinkpad@linux-thinkpad.org
Wed, 08 Apr 2015 13:40:51 -0400

On 04/08/2015 01:25 PM, Richard Neill wrote:
> I recall using this in a R60 some time ago. The Network card has the
> hardware built in (I think it was part of the Broadcom PHY), and it
> was a neat (though quite deeply hidden) option within the BIOS
> diagnostics to test cables - and indeed, I used it to find the break
> in a very long cat 5 cable (it located it, correctly, within 50cm in a
> 65m cable run). The R60 also had support for doing this within the
> network driver's advanced tests in Windows. Sadly, Linux didn't
> support it.

That still requires hardware to do the testing.  Software alone won't do
it.  I mentioned it was possible to make a TDR with just a 'scope and
pulse generator.  That is entirely possible, but modern instruments use
software to control TDR and analyze the results.  With the basic TDR I
mentioned, you'd have to do that yourself.  For example, many years ago,
I worked in a telecommunications company where open wire lines were
still in use.  A common practice was to have a lineman go out along the
line to introduce faults.  The tech would then record where on the
'scope waveform that fault appeared.  That info would then be used
later, to help locate real faults.  A modern instrument will give you an
accurate distance automagically.