4, as the E side is so poor ADSL just works ADSL2 would require the use of 2 pairs so the line plant would come under massive pressure as they just don’t have the wires in the ground to cope with a role out.
Nope, ADSL/ADSL2 is ALWAYS provided over ONE PAIR of wires, I.E. 2 WIRES that are already coming to every house. Unless it is a specialist bonded service which is different...
All that ADSL2 changes is the frequency which is used over the COPPER PAIR.
Another thing, it was post office telephones in the early days, else why would the old man hole covers say Post Office Telegraphs, PO and GPO on them, also the oldest green PCP cabs say PO on them.... Research...