Lurch wrote:

ADSL is carried at a radio frequency (RF) so will effectively 'jump'
gaps in cables.

At the very low radio frequencies used by ADSL (~30 - ~500 kHz, AIUI)
the signal attenuation involved in 'jumping the gap' in a broken wire
will be huge[1]. What's far more likely to be happening is that the
stray capacitance of the o/c wire (on the subscriber's side of the
break) to earth, or, more particularly, to all the other pairs in a
multi-pair cable, is providing a 'return' connection.

For an electrical current to flow you are quite correct though.

Well someone needs to point out that a one-wire connection still depends
on the flow of electric current ;-) How do you think aerials work?


[1] The ADSL modem in my roota usually claims an SNR margin of around 30
dB, so clearly there is a lot of margin in the system. Capacitive
coupling across the gap in a broken wire at these frequencies though is
going to introduce probably 60+ dB of attenuation - so that isn't the
answer...

--
Andy