First of all telephone is not required for a brodband.
what we do need is a medium for a broadband internet to connect,,,
Various broadband medium used are..
1 One pair copper cheapest of all [ dsl/
adsl/dialup used by Airtel,BSNL,Reliance ] can also be used for telehones
2 Four/two pair copper [CAT5 -Lan Sify, Hathway etc ]
3 Fiber optic [very expensive mainly used for backbones , ALL ISPs infact all of worlds internet is backboned on fiberoptic cables even long distance calls]
4 Wimax may become cheapest once its popular [Wireless , Reliance,
tata, sify etc , its like wify with range as high as 3 kms ]
we need no telephones phone for broadband...
the mediums above, As can see one pair copper wire is easiest to setup and maintain and its setup is similar to that of telephone lines .
So companies can provide telephone on the same line
Although no telephone line is required why don't use the same network for fifferent service and charge customers lol ...
its just a companies money making strategy to provide telephone along with broadband.
hope u got ur answer
i understood ur point
y wa broadband available 15 years ago?
bsnl had all infrasturcture ,then y has it started off late