I think we've got the internet problem solved. We recieved our new filter today, and it came with a little wall mount. Keeping in mind not to hook up the filter to the DSL modem, what we did was hook up the wall mount thing (we didn't mount it, though) to the telephone jack. The wall mount had a plug to plug in the filter, and on the side, had a plug labled "DSL", and it had a picture of a DSL modem under it (so I assumed the DSL modem was supposed to plug into that plug). So, we plugged in the phone into the filter, and then plugged that into the wall mount. We then plugged the DSL phone cable into the side plug on the wall mount (labled DSL), and shortly after that the internet came back up (and rather quickly, I might add). Hopefully our internet problems are solved for good.
