NTL does provide an ADSL service over BT line, I have it and am using it right now
NTL Freedom Broadband.
general ADSL modem/router settings
VPI=0
VCI=38
ENCAPSULATION MODE= (PPPoA) RFC2364
MUX=VC
MTU= 1458 or 1500
Use the FULL user name and addy for log in that you were provided with, which will be like this:-
yourusernamehere@adsl.ntlworld.com
and your password.
If its a router for a cable connection a standard router will do and you
cannot use an adsl modem/router.
i hope this helps.