This evening a Comcast Rep Told Me
that while I could not get backup batteries through Comcast for my XB3 gateway, if I brought it in to a Comcast store, I could swap it for free for an XB6, then call 1-888-972-1261 to buy a backup battery for that one so my residential voice service through Comcast would not constantly be offline everytime the internet goes down. She said the battery cost is $164. Is this true? Has anyone done this?