Per the FAQ on the Tivo Website:
What signal sources does the TiVo HD DVR support?
The TiVo HD DVR supports digital cable, over-the-air digital antenna (ATSC), analog cable and analog antenna. You will need one (1) Multi-stream CableCARD or two (2) Single-stream CableCARDs to receive HD Digital channels. Without CableCARDs, you will still be able to receive standard definition analog channels, as well as analog and digital antenna channels.
Here's my situation. I have DirectPath Cable. I have no information on these people, and their service is....interesting. They don't offer HD packages, or DVRS, or anything you'd expect from a provider. When I ordered service, All I asked for was "everything". They call it their Digital Package, but I have no idea if any of them are actually digital. I have a new S2 hooked up to it now, and have never had an issue recording two things at once, on any channels. Maybe that's just an anomaly, but I don't know if that means all of my channels are analog or what.
The current setup is Cable from Wall <> splitter<> cable one to Tivo <>Cable Two to Cable Box.
Will a DTV work with this setup? How do I know before dropping $300.00?
I have called DirectPath and the CSR had no idea what cable cards were, put me on hold, and said they don't provide them.