Things I have tried:
1) Starting configuration with static IP or dynamic IP, router connected to 5268 LAN port works as expected
2) Network dynamic IP, set 5268 to bridge mode, router to DHCP. Result is no internet connectivity.
3) Try a different router, same result.
4) Try connecting computer directly to 5268 with network set to DHCP, same result.
5) Repeat above with static IP. Enter IP, gateway and DHCP server info manually in router or computer networking settings.
Sonic support tells me that they can see the 5268 is in bridge mode but there is no sign of the downstream equipment. I have used the same wiring interconnects for all the above variations so I believe it is sound. Both routers have a history of working perfectly with a Comcast cable modem in a different location and similarly the computer has been trouble free for connectivity in all cases, including when used with the Pace 5268 as a router.
I am out of ideas, so any helpful tips that will allow me to use my own router directly (for a multitude of my own reasons) would be greatly appreciated.