Earlier today, I helped a Comcast customer set up her wireless network at her new home.
I ran into unexpected difficulty configuring her TimeCapsule to serve as her wireless router. I originally thought it was a simple matter of connecting an Ethernet cable from the ARRIS TM502g cable modem to the WAN port on the Time Capsule and use AirPort Utility to finalize the connection. No such luck. The AirPort Utility kept on responding with a self-assigned IP address in the 169.254 range.
After I reset the Time Capsule a number of times, I called Comcast support. I learned that it is necessary to remove the power cord AND internal battery from the ARRIS modem for 30 seconds in order to resynch the signal. Removing and replacing the battery cover proved to be a bit of a challenge. It took me 15 minutes (I’m not kidding) to complete what you would think would be a simple procedure. Once I was able to close the battery cover, configuring the Time Capsule for wireless access was a snap.