.......Hopefully I'll get an explanation.
It can happen so I have found out on these forums. ADSL can work on one wire apparently, so voice could be lost totally.
When a new line card was fitted did he give it that last extra push and wiggle? That thousandth of an inch can make all the difference. I found that was the issue for a graphics card many moons ago.
Really (being genuine), I'd like to know how that is achieved. Seeing that most Routers are not earthed and/or have no electrical reference to a "common" hot or cold earth**, their only connection to the BT infrastructure is via a BT connection. I can only assume that there is still an "effective" connection ie two wires connected (albeit one high impedance - if that were the case). The only other explanation (I can think of) is that adsl routers have a high impedance input and they can interpret the high frequency part of the total bandwith (around say the 1Mhz area) i.e. as though the input was acting as an aerial. I'd be surprised if it were possible to work in a "aerial" fashion that it wasn't very crippled, ie the tones it could use/available were limited..
Edit:-
** Just thought of something and also the reason why some people get a tingling sensation from their laptop.
A lot of the Power Supplies (bricks) these days for Routers/laptops etc are "switch-mode" and those that aren't earthed often use an "Y" capacitor between hot and cold earth. With that in mind, our Mains neutral is effectively earth and there will no doubt be a reference to earth by the BT infrasructure. So in theory one BT wire connection could work if certain criteria were met. I would expect it to affect the adsl connection performance wise if it was working in that fashion - badly.
Edited by Vorlon (Mon 10-Aug-09 19:14:42)