Introduction
CAM-modules are meant to decode certain coding systems. You need a Irdeto CAM to decode Irdeto broadcasts. And if you want to decode Seca broadcasts, you will need a Seca CAM. But keep in mind. It will take more than the correct type of CAM alone to view a coded broadcast. So you will not only need a Seca CAM to view a Seca coded broadcast. You will need a valid smart card too.
And now that I'm at it, I would like to take the opportunity to correct a very common mistake. It is not the CAM, nor the card that decodes/unscrambles the movie, documentary or whatever it is you are watching. It is the MPEG decoder in your receiver which takes care of that.
Say again?!?!
Yes, I can almost hear you think "what the heck are the CAM & card used for then?".
Well, the CAM and card are only needed to tell the receiver if it should or should not decode the MPEG stream.
Do you remember this picture from the first chapter?
This picture shows you exactly what happens. Let me explain.
On the left side you see an encoder. That is the MPEG encoder which scrambles the signal into a MPEG stream.
The next step is the Scrambler. Here the subscription information is added to the MPEG stream.
Now the whole signal is modulated and broadcasted.
Your dish receives the signal and sends it to your receiver.
The receiver de-modulates the stream and checks to see if the MPEG stream should be descrambled conditionally (for subscribers only) or unconditionally (Free To Air).
That conditional descrambling, that is where your CAM & card kick in.
For general understanding, I will first give you an example of an almost identical system you all know:
Imagine yourself shopping in a supermarket. You put all the goods you want in your shopping cart. Now you go to the pay-desk, you get your credit card and put it in the pay-terminal, key in the correct pin code and wait for the answer: Go or No-Go.
Now how does that match the SAT world? A step by step comparison:
- The CAM is the card terminal
- The SAT-card is your credit card
- The broadcasted signal is the shopping cart
- The receiver/decoder is the cashier
- You take your filled shopping cart to the pay-desk (the signal does arrive at the receiver)
- If you have any items in your cart, they are entered by the cashier (the signal is checked if subscription validation is required)
- To pay your shoppings, put your credit card in the card terminal (put the SAT-card in the CAM)
- Enter the pin code and pray for sufficient balance ;) (the subscription data on the card is checked)
- If the card terminal approves, the cashier will let you take your shoppings home (the receiver will unscramble the signal)
Now before I introduce a misunderstanding here, I need to tell you that this information is not entirely accurate. The card itself does not actually contain all the subscription data. No, the card contains a set of keys, the end date of the subscription and an indication for the channel-bouquet that you subscribed to. That is all the info that is needed to reply with a correct answer when the CAM requests that answer.
Are you still with me? Great!
When the CAM checks the card for a valid subscription, what it really does is ask for a certain key. If the answer from the card matches the expected answer, the subscription is assumed to be valid and the signal is unscrambled.
So this validation of the card/subscription is one task that is performed by the CAM. But the card needs to be updated on a regular basis. After all, you might cancel your subscription one day, or choose to subscribe to another bouquet. Or maybe you stopped paying your subscription dues. All of these situations require updating of the subscription information on the card. That is done by the CAM too.
The way the CAM and the card communicate, depends on the type of encoding that your provider uses. That is where the names like Irdeto, Seca, Viaccess etc. come in. They are in fact advanced registration systems. They make sure that your card is constantly updated so that you can view those channels that you have subscribed to. And because these Conditional Access Systems (or CAS) are commercial products, there is a lot of competition, resulting in a lot of different systems and therefor a lot of different CAMs too.
If my explanation has been clear, you will understand that if you want to know what CAM you should choose, you first have to decide what channels you would like to receive. In other words, which provider do you fancy and want to subscribe to. As soon as you have made up your mind about that, you need to find out what coding the chosen provider utilizes. In the links section you will find link to sites that provide such information.
Now that you have made your pick, you can go out to buy the CAM of your choice.
Here you see some examples of CAM's.
And now that I'm at it, I would like to take the opportunity to correct a very common mistake. It is not the CAM, nor the card that decodes/unscrambles the movie, documentary or whatever it is you are watching. It is the MPEG decoder in your receiver which takes care of that.
Say again?!?!
Yes, I can almost hear you think "what the heck are the CAM & card used for then?".
Well, the CAM and card are only needed to tell the receiver if it should or should not decode the MPEG stream.
Do you remember this picture from the first chapter?
This picture shows you exactly what happens. Let me explain.
On the left side you see an encoder. That is the MPEG encoder which scrambles the signal into a MPEG stream.
The next step is the Scrambler. Here the subscription information is added to the MPEG stream.
Now the whole signal is modulated and broadcasted.
Your dish receives the signal and sends it to your receiver.
The receiver de-modulates the stream and checks to see if the MPEG stream should be descrambled conditionally (for subscribers only) or unconditionally (Free To Air).
That conditional descrambling, that is where your CAM & card kick in.
For general understanding, I will first give you an example of an almost identical system you all know:
Imagine yourself shopping in a supermarket. You put all the goods you want in your shopping cart. Now you go to the pay-desk, you get your credit card and put it in the pay-terminal, key in the correct pin code and wait for the answer: Go or No-Go.
Now how does that match the SAT world? A step by step comparison:
- The CAM is the card terminal
- The SAT-card is your credit card
- The broadcasted signal is the shopping cart
- The receiver/decoder is the cashier
- You take your filled shopping cart to the pay-desk (the signal does arrive at the receiver)
- If you have any items in your cart, they are entered by the cashier (the signal is checked if subscription validation is required)
- To pay your shoppings, put your credit card in the card terminal (put the SAT-card in the CAM)
- Enter the pin code and pray for sufficient balance ;) (the subscription data on the card is checked)
- If the card terminal approves, the cashier will let you take your shoppings home (the receiver will unscramble the signal)
Now before I introduce a misunderstanding here, I need to tell you that this information is not entirely accurate. The card itself does not actually contain all the subscription data. No, the card contains a set of keys, the end date of the subscription and an indication for the channel-bouquet that you subscribed to. That is all the info that is needed to reply with a correct answer when the CAM requests that answer.
Are you still with me? Great!
When the CAM checks the card for a valid subscription, what it really does is ask for a certain key. If the answer from the card matches the expected answer, the subscription is assumed to be valid and the signal is unscrambled.
So this validation of the card/subscription is one task that is performed by the CAM. But the card needs to be updated on a regular basis. After all, you might cancel your subscription one day, or choose to subscribe to another bouquet. Or maybe you stopped paying your subscription dues. All of these situations require updating of the subscription information on the card. That is done by the CAM too.
The way the CAM and the card communicate, depends on the type of encoding that your provider uses. That is where the names like Irdeto, Seca, Viaccess etc. come in. They are in fact advanced registration systems. They make sure that your card is constantly updated so that you can view those channels that you have subscribed to. And because these Conditional Access Systems (or CAS) are commercial products, there is a lot of competition, resulting in a lot of different systems and therefor a lot of different CAMs too.
If my explanation has been clear, you will understand that if you want to know what CAM you should choose, you first have to decide what channels you would like to receive. In other words, which provider do you fancy and want to subscribe to. As soon as you have made up your mind about that, you need to find out what coding the chosen provider utilizes. In the links section you will find link to sites that provide such information.
Now that you have made your pick, you can go out to buy the CAM of your choice.
Here you see some examples of CAM's.
