Power down everything. Plug the Linksys direct into the modem power up the modem. Wait for it to sync. Power up the ATA. See if it connects then... Modems generally need to be rebooted to clear them when you change devices plugged into them. Is this an RT31P2 you have? Try to plug a computer into one of the lan ports, reboot, and try to surf the net, as to verify that it does or doesnt work. Need to rule things out.