How Do I Use My Tivo With Voip (Wireless) Without Installing a Router?

I have Tivo service and I don't want to install a router. I have VOIP through wireless internet provider. What cable or equipment would I need to plug my tivo into something & dial up via voip? I have not seen an internet phone with an extra rj11 hook-up.
I have tried manually dialing the tivo #, but I can't get the 2 modems in synch with each other over the VOIP connection, any suggestions?