CableCARDs slide into the back of compatible TVs and DVRs. About the size of a thick credit card, these small devices decode encrypted digital cable information so that you're able to watch it on your TV.

What is a CableCARD?

A CableCARD is a tiny device that decodes encrypted digital cable information so that you're able to watch it on your TV. You can rent one from your cable provider for a small monthly fee.

About the size of a thick credit card, a CableCARD plugs into the back of Digital Cable Ready (DCR) components, such as digital TVs or digital video recorders (DVRs). Using a CableCARD instead of a set-top box means you'll have fewer A/V components taking up shelf space, plus one less remote control to worry about. You'll also see a small improvement in picture quality. Today's CableCARD devices are one-way — that means you can't take advantage of certain services that require two-way communication, including Video-on-Demand (VOD) and your cable provider's interactive program guide. However, this should change shortly with "CableCARD 2.0" (more on this later).

In order to get a CableCARD, you'll need to call and set up an appointment with your cable provider. Since CableCARDs are still an evolving technology, there are still a number of things that can go wrong — that's part of why cable companies don't allow self-installation. You'll have to pay an installation fee, ranging from about $25-40, depending on your cable provider. But if you do encounter any complications while installing the card, the technician might be able to fix it then and there.

How it works

While CableCARDs do more or less the same thing as a digital set-top box, the decryption process is a bit more complicated. Once the CableCARD receives the encrypted signal from your cable provider, there are three more steps before you can see video on your TV:

• Decryption: The CableCARD receives encrypted digital programming information and decodes it.
• Re-encryption: The CableCARD re-encrypts that decoded information and passes it on to the CableCARD-ready TV or DVR, along with a decryption key.
• Decryption: The DCR TV or DVR receives the re-encrypted information and uses the decryption key to decode it.

Re-encryption is one way that cable providers prevent their service from being stolen. In order for the CableCARD to pass on the decryption key to your DCR TV or DVR, it has to be activated by your cable provider. Activation is what tells the CableCARD that it's OK to pass on the decryption key and allow you to watch the channels you subscribe to. It's a two-part process:

• Pairing: Matches the CableCARD to one specific DCR TV or DVR. Pairing tells the CableCARD that it's OK to pass on the decryption key for the channels that you're paying for.
• Authorization: Tells the CableCARD which channels you're paying for as part of your programming package, i.e. which ones you're authorized to watch. It will pass on the decryption key for those channels only to the DCR TV or DVR that it's paired to.

What kind of CableCARD should you get?

CableCARDs come in two varieties — single-stream and multi-stream, known as S-Cards and M-Cards, respectively. S-Cards can only tune in one channel at a time, so they don't allow things like picture-in-picture or the ability to record one program while watching another if you're using a DVR. M-Cards, on the other hand, can tune in two channels simultaneously, so you don't lose the aforementioned features. If you often take advantage of things like picture-in-picture, be sure to mention this to your cable provider so you get the right type of card.

CableCARD 2.0 — upcoming 2-way functionality

CableCARD-compatible devices such as CableCARD-ready TVs are currently one-way. They don't allow communication from your end back to the cable company, so you're not able to enjoy interactive program guides, pay-per-view programs, or Video-on-Demand. However, this should change shortly with "CableCARD 2.0" or "tru2way™." Upcoming CableCARD 2.0-certified cable boxes, televisions, and DVRs will allow two-way communication, so you'll be able to enjoy many of the features you may have grown accustomed to with a conventional digital cable box.

Now, the term "CableCARD 2.0" refers to the host device — the CableCARD-ready TV or DVR — and not the actual card. (CableCARDs themselves are and always were designed to support two-way functionality.) It's an important distinction, and here's why: If you currently have a TV equipped with a CableCARD, your television can only receive a one-way stream. Since CableCARD 2.0 isn't an actual card, changing CableCARDs at some point in the future won't help. If you'd like to enjoy things like pay-per-view and Video-on-Demand with your current TV, you'll need to get a cable box or DVR that's capable of two-way communication.

CableCARDs and cable boxes

On July 1, 2007, a new FCC mandate kicked in which requires all newly manufactured digital cable boxes to be compatible with CableCARD. This could benefit consumers by allowing them to purchase their own cable boxes and DVRs. You'd be free to buy whatever box had the features you're looking for, and you wouldn't have to return that DVR with hours of recorded programs if you move and change providers. After buying a box, you would contact your cable company for the CableCARD, and the card would give you access to your provider's cable system.

While cable boxes are not currently available for sale at retail outlets, the ones provided by cable companies will also include a CableCARD. However, the new law does not require cable companies to replace their existing inventories with CableCARD-compatible boxes, so it may be some time before cable companies deliver these boxes to consumers. But don't be surprised if your next cable box includes a CableCARD slot.

Learn more about CableCARDs in your area

If you're interested in CableCARD, it might be useful to do a little research beforehand. Some providers are better than others at addressing CableCARD problems. Here are some ways you might be able to find out how your cable provider measures up:

• Call your cable provider and ask them about their CableCARD service. Get the name(s) of the person or people you speak to, and ask about the specific product you want to install the card in. Have they had other successful installations in the area? You probably won't find a wealth of knowledge, but it might be a good way to find out ahead of time how your provider deals with CableCARD questions and concerns.
• Ask friends/neighbors/coworkers who have CableCARDs how their service is going.
• Look online for people in your area with CableCARD service. We've found AVS Forum to be a particularly useful resource. You can search their discussion boards for your specific area and cable provider. If you can't find a specific discussion for your area and provider, try posting a question. Include your area and provider as well as the TV or DVR you want to install the card in.
• Do a generic search for your cable provider and area using your favorite search engine (ex: "CableCARD Chicago").