Phone DSL Wiring question - TWISTED PAIRS

I had an internet issue today. I moved a jack to bring my wireless router/modem closer to my PC. After installing the jack worked fine for phone but I couldn't connect to web. Moving it back to the old location, I was able to connect fine. So I called ATT (its Uverse internet) and they confirmed that it was a phone wiring issue. Knowing that when I wired the phones, the phone company signal comes in on two - two wire twisted pair. That is, I have dial tone on two pairs. Is one for internet and one for phone? When I moved the modem to the new location, I believe that jack was controlled by the other twisted pair that supplies the jack where the modem usually sits.