He's right, though. There is a filter has to go on the voice lines to prevent interference. If the house is daisy-chained, DSL has to be on the first outlet, so that the filter can protect all up-stream phones.
Correct me if I am wrong, but I thought you can plug the DSL modem directly into any jack in the house and then you get a package of multiple filters with the install package that go inline between the line cords and the jacks of other phones to filter out the DSL?
