The Dual concept is to fully prepare the TV-distribution infrastructure for a 2nd CAS to be introduced if facing security or support issues with the original CAS....

If piracy hits, damages can only be minimized through resolute action. A significant loss of subscribers and revenues may otherwise occur. Also, content related costs may increase.When security has been restored, lost subscribers have to be re-acquired, implying larger costs the more subscribers were lost.
If the CAS has been penetrated, the only countermeasure may be to replace the entire CAS system including all smart cards.  Once such decision is made, the swap should be swift.

A few questions to ask before starting the swap operation are:

-    Is my CAS vendor ready with an adequate replacement?
-    How different is the replacement CAS from the pirated CAS?
-    What are the commercial conditions for swap?
-    Do I reallly want to continue the relationship with the present CAS vendor?

This is where Dual provides a fresh approach:
a new CAS can rapidly be run into operation for all Dual prepared STBs,without consent or action from the original CAS vendor, forcing the pirate back to square one.

The most important Dual preparations are:

• Make STB OTA be under operator control – not under CAS vendor control. This allows software support for a 2nd CAS to be uploaded over air.[The operator may consider trusting the STB manufacturer OTA control.]
• If pairing is used, require the pairing keys from the CAS vendor including instructions for how they can be used.
• Include in contract with the CAS vendor:

- the CAS is DVB SimulCrypt compatible throughout,
-   a 2nd CAS can co-exist in the STBs, or be loaded OTA,
-   pairing keys are given to the operator, and allowed used at any time by  another CAS.

• Preferably test the STBs for being ready for Dual.

Before actually swapping or running two CAS, there are some preparations not involving the first CAS vendor:

• Check that the transmission system is able to run two CAS[Normally in place]
• Make the subscriber management system able to address two CAS
• Make any EPG or interactive applications prepared for both CAS.

Simulcrypt is the ”solution” often promoted as the 2nd CAS opening. However, Simulcrypt normally enables new CAS to be introduced on new STBs only.  It does not provide sufficient mechanism for the CAS to be swapped on existing STBs. So, unless preparing for Dual, one is still stuck with the first CAS vendor.

Unlike Simulcrypt - with Dual the rescue CAS is ready for replacing the original CAS on all STBs – not only new STBs.
Dual weakening the security level?Quite the contrary, as Dual allows the operator to choose whether to:

i)   continue with the 1stCAS vendor if the upgrade of the CAS is convincing, or
ii)  introduce a 2nd CAS vendor providing a more secure CAS and/or a faster replacement to curb piracy before allowed to spread.

Thus, Dual does not weaken security – rather Dual may improve security! 
And: Dual does improve competition on price and service.