Can be worked out from the attenuation and will assume a certain attenuation per km of cable.

There are probably three ways I can think of to measure it with reasonable accuracy: Would any give resilution of 1m? unlikely.

A tape measure

TDR (time domain reflectomenter). There may be a cheap TDR implemented in the modem ... it would give reasonable rsults however they need interpreting correctly.

Ultra accurate measuring of a ping - altrhough for 10 metres that would be 33nS (or there abouts) and does not account for any processing/switching time.


Someone else may have another sugestion.

In reply to a post by MrSaffron:

Can be worked out from the attenuation and will assume a certain attenuation per km of cable.

As you say the attenuation per km would have to be assumed although in reality cable attenuation can be affected if aluminium is used for some or all of of the D side and also if different thickness of the conducting pair is taken into consideration.

That would be a big assumption ... underground cables can have 19, 22, 24, 26 AWG - 0.9, 0.63, 0.5, 0.4 mm diameter and the atteuations will be massively different from around 28dB/km down to 12dB/km at 1MHz with a simlar variatioin at te standard 300kHz point. And as is often te case there will be more than one size in any cabinet to house.

It is a big assumption but its the calculation they make

If that is the case then the 563m referred to could be anywhere from 250m up to 1.2 km - so a totally pointless figure.