I would want to start with a clean slate on the AirPort before connecting it. Also many will have connected a PC to the TM502G and that creates a problem. The MAC ADDRESS (which I will not define what that is since you can use google.com) is then locked onto and if you don't power cycle the TM502G it will not work with any other PC or router!
The reset of the Air Port is likely since DSL modems need a PPPoE login system...
I'm having problems getting my AirPort Extreme to work with my Arris Modem (Model TM502G). I previously had the airport connected to a DSL modem.
I'm guessing something needs to be reset with the airport, but have no idea what -- or how.
I already tried the reset button on the Arris with no results.
Anyone have any ideas?