No, comcast cable is encrypted and therefore un-recordable. I did a test to verify this. I went to my grandmother who has comcast digital cable. (She's always been ahead of the curve) Anyway, I used a mythtv+ubuntu box with a haupuage 1250-mc digital tuner and tried to tune the digital. The result? Nothing. Only the free channels came through. I tried every variation of tuner settings I could think of like Qam-256, 128, etc. Broadcast freq table, cable freq table. Basically, none of those channels worked. What I found interesting was that her lcd tv was able to tune most of those channels without using a set top box, yet my digital tuner card could not. As of right now, I'm convinced that digital TV from comcast cannot be recorded by mythtv in a reasonable fashion. Please, if you personally have a tuner capable of tuning comcast digital cable, let me know as I am prepping the wiki page to say that digital tuners won't tune non-OTA channels.