Before installing the D-Link DIR-615 I updated its firmware to the latest revision (Hardware Version: C1 Firmware Version: 3.13NA). This was the cable modem/router I used before subscribing to Comcast's Xfinity triple-play and using the Arris TG862 that supposedly worked best with Comcast telephony.
The Obi202 was installed and tested in parallel with Comcast Voice before porting the telephone numbers out to Ting, Google Voice, and RingTo. After porting, I terminated the Comcast Voice subscription and had the Obi202 working with both numbers using only the modem/router functionality of the Arris TG862.
I am not averse to buying a new cable modem/router if the D-Link DIR-615 is not suitable for telephony purposes, and replace the DIR-615 with a newer model which would enable gigabit switching for NAS. But most of the network is set up for fast ethernet, and a gigabit upgrade is otherwise not necessary. I also have Linksys and SonicWall modem/routers in standby inventory.
Given that the Obihai/D-link glitch has killed land line telephone service at the house, and my Sprint Airave also was a victim of the network reconfiguration, I am under a lot of pressure to get the Obi202 working with the DIR-615 or another more compatible modem/router. I am not inclined to run the entire network (about 2 dozen devices including Unix and Windows servers) through the Obi202's router, whether bridged or not.
I have opened an Obihai support ticket to help determine if the D-Link can be reconfigured to play with the Obi202, but if it cannot, I would appreciate any recommendations regarding other modem/routers to purchase.
Thanks again for your helpful suggestions.