I recently upgraded to Triple Play with phone service from Double Play with just cable and internet and I got my new Arris TM822 modem self install kit today. I had no problems setting it up and activating with my computer connected directly to the modem. When the modem is directly connected to my computer via an ethernet cord, all lights are green and the "link" light is blinking. When I connect the modem to my WRT54GS wireless router via an ethernet cord, the link light turns amber/orange and it won't connect.
I have tried powering down and resetting both the modem and the router, but that did not do anything. In searching online, I saw one forum that suggested connecting the modem to the router and then connecting the router to the computer via ethernet cord, doing a reset on the router, then going to the router gateway and do a MAC Address Clone. I did that (at least I think I did - it said settings saved), but the link light is still blinking amber/orange and it won't connect.
The router was connecting and working fine with my old internet only modem this morning.
First, you need to reset that modem by using the recessed reset button on the rear each and every time that you change the device that is being directly connected to it. You'll need something like a bent paper clip or a pen tip. Depress and hold it in until you see the front panel indicator lights begin to cycle, then release. Now give the eMTA the time it needs to re-sync.
Second, that older router does not have a Gigabit WAN port as does your NIC so the light is that color. You may want to consider updating it for one that is more current.