As far as I know, Comcast does not use SDV in Howard County. I would call Comcast and have them re-hit the CableCards on your Tivo.
Comcast's service options look something like this:
- Basic cable (locals including HD + gov't channels) - $10-$15/mo
- Extended basic (most common nat'l channels) - Extra $35/mo
- Comcast Digital (numerous digital filler channels + HD versions of extended basic channels; also includes one non-HD STB or CableCard ) - Extra $10-$16/mo.
Comcast CSRs are trained to quote all three packages together when you ask about digital service. The first item is required for TV service. However, in most service areas, you can ask for just (1) and (3).
Until recently, many customers could get cable channels like Discovery Theater HD, TNT-HD, ESPN-HD, and ESPN2-HD with just packages (1) and (3).
Unfortunately, this was a error in Comcast's authorization system. Comcast was never allowed to sell Discovery Theater HD, TNT-HD, ESPN-HD, and ESPN2-HD to customers without the standard Discovery, TNT, and ESPN channels in package (2). Content providers do not sell the HD versions separately, they are bundled together with the SD versions (ex: Comcast pays $2.75 for ESPN and ESPN2 and gets ESPN-HD for $0.25 and ESPN2-HD for $0.10).
This month, Comcast began to 'fix' that on its cable systems. By the end of September, you will no longer get Discovery Theater HD, TNT-HD, ESPN-HD, or ESPN2-HD on any HD STB or HD DVR without a subscription to (1), (2), and (3).