Linksys 1200 Router On Telephone Don't Work

Right now I have a westlll a90 750022 router working on a vista computer working fine but that's a rental. I have bought a Linksys E 1200 series router. The problem is now that when it is all hooked together our phones doesn't work, just dead that is, neither does the router.The router westell A90 from Century Tell works with a dual plug in, a DSL filter, the plug has one side for the phone line and the other for the DSL modem, in other words the westell router cannot be directly connected to the phone line.