Unfortunately, there are three (3) ways to activate IR in Xfinity!
Xfinity is usually code 1014 in Flipper V6 and 3084 in Flipper V7 and above (version is on the back).
But Xfinity is usually installed in RF (radio frequency). Flipper is an IR (infra red) remote. See other Xfinity articles for Favorites format.
So we need to activate IR in the Xfinity. The following methods depend on your box:
1) Use Xfinity remote to change settings in box: Menu>Settings>Remote Control>Activate IR.
2) Some remotes have a setup button: press hold Setup button until light solid, then enter 987. But check with Xfinity for this code.
3) Arris XG1v4-A box: Press and hold A and D buttons at the same time, LED goes from red to green and press 987. Note, this will disable Voice Commands. The IR receiver is very sensitive in this box, so you ay need to purchase an IR Repeater. See other Xfinity articles for the IR Repeater / Extender.