The vast majority of the time, the issue is with either the Installer or the CableCARD.
I use a CableCARD inside my Sony DHG-HDD500, and I remember reading through the system menu's and I could tell that it wasn't enabled, yet the guy on the other end kept telling me he could tell it was enabled. They had never sent the correct pulse to sync up.
After the third call on the second day I got a tech that at least had the brains to listen to what I said. They sent a new sync request and its worked perfectly ever since.
There have been some people who have had issues with the Cards themselves but this seems to be less common, and I'd guess that the swapping out cards and getting one that 'works' also has a bit to do with the cable company not enabling the cards correctly in the first place.
Note that the S3 has received certification via Cable Labs and they have rigorous interoperability testing in order to pass. So, the S3 should be able to interoperate with any Cable System using CableCARDs provided by the Cable Operator. That being said, you may end up with a dumb arsed tech and have to go a few rounds in order to get it working.
- TiVo HD (750GB) 7/07
- TiVo HD + 1TB Ext 11/09