just installed my "new and faster" Xfinity modem. It works only if connected directly to my PC but when i hook it up to my Linksys Wireless G broadbad Router (model wrt54g) i do not get an internet connection. Is there a compatablity issue between the two. I do not have this issue when i hook up the old modem.
This answer exists throughout the forum, in many threads,
If you change the device connected to the modem, you need to power cycle from the wall out. If the Xfinity modem is an eMTA (including phone service), then you need to power cycle it using the recessed reset button. (Due to the battery backup in an eMTA.)
Power cycle the modem, then the router. When all have settled in (lights lit steadily is the general indicator) then boot up the computer.
The newest Xfinity modem (black, stands vertical, & has a vertical row of light blue lights) that's shipped from a warehouse, is also a wireless router. I have one. Call 1-800-COMCAST & ask them about one. Shipping is $9.95 & the old modem will ship back free by just taking it to the UPS Store.