This is a new feature that comes with most HDTV displays allowing you to eliminate the cable box from your bill and your system creating a significant monthly savings and extra rack space. Most cable cards rent for a few dollars a month. Depending on your cable company you will be provided the card for you to install, a simple insertion on the back of the product, or they will send out a service rep. Once installed the cable company must setup your account to activate it. If done right away, as in most cases, it should start working within minutes to possibly an hour.
Cable Cards use the same PCM/CIA connection and slot that laptop computers provide for expansion. On a laptop it is obvious which way the card goes in but that is not the case for a cable card product. While this device is keyed it is possible to force it in backwards damaging the card and/or receptacle on the product in which case the product will need to be repaired and/or cable card replaced. If you are installing one it should slide in easily with a final 1/4 inch of effort to seat the card connector into the jack. If there is any effort to slide it in then either you are not lining up the card properly for insertion or it is backwards.
At this time cable cards are one way communication devices meaning they do not support VOD - video on demand or PPV - pay per view services. If you want to receive these types of services you must use a cable box. Two way cable cards are on the way but have been delayed due to technical issues which can still linger with the one way devices. It has been a very tough two years for the cable providers and manufacturing industries as they worked together resolving the problems of implementing universal standards for this system. Based on that experience, if you are having problems it is more than likely due to your cable company.
TECHNICAL
A cable card is actually a computer modem device that receives data from the cable company using a different and exclusive carrier on the cable system which is already there and required for their cable boxes. Non functioning or intermittent cable cards have problems for only two reasons in most cases. Either the exclusive carrier is too noisy to function properly or the cable company is not setting up the data right in their system to properly activate it.
A cable card receives the channel map from your cable company so you can find your channels exactly where they should be as listed and provided by the cable company for your QAM cable tuner. The cable card also determines what pay channels and services you will be allowed to view.