Try these:

bd/dvd    35278
game    62409
sat/catv    15560
video 1    08393
video 2    65993
tv    45257
sacd/cd    08137
tuner    07881

Your Comcast remote can't do the USB input code unless you buy a JP1 cable ($8 on ebay).

My codes came from here (need join the forum to download and need to install Remote Master software to view the file). All will work on your Comcast except the ones that use Sony20 protocol.

[Link: hifi-remote.com]