Can't find it anywhere on Comcast, and I have all the channels I think ...
The SEC Network alternate channels are 768 and 787 on Comcast, 810/811 on Charter, also on DirecTV (Ch. 611-1) and DISH Network (Ch. 596/597 & 404.1-404.2 on the Hopper), AT&T U-Verse (Ch. 608/1608 & 609/1609) and Verizon FiOS (Ch. 332/832).
810 or 811 on Charter I do believe.