U-Verse Data Cable

I have AT&T U-Verse, and I need to move my modem to another room. My issue is I can not find a clear answer as to what cable I need to buy, that runs from the phone jack to the modem. I called customer service and all they were able to tell me is i need an RJ14 data cable, and searching that doesn't help. I bought a normal phone cord and that did not work. I've searched and can't find a clear answer, I've found some that should work through amazon but i don't want to make that purchase unless I know it 100% will work. Can anyone help me with this. Thank you in advance.