Hello,
the voice and ADSL signals should be separated by your provider, of course there is a remote chance that something is wrong at the providerĀ“s end, but I would check your equipment first. How is your splitter connected to your ADSL modem and your phone line ? Make sure that the splitter is connected as following:
Computer --> ADSL modem --> Splitter
Telephone --> Splitter
That is, make sure that the splitter is not placed between the computer and the ADSL modem.
Which platform (e.g. Cisco 1721) and which IOS are you using. Can you post your configuration ?
Regards,
GP