Conditional Access System

Conditional Access System (CAS) or Addressable System is a description
normally used for a set of hardware devices and connected software (including a set top
box) used at different stages of distribution of a TV channel through which normally the
pay channels are transmitted in encrypted form. The subscriber is given an authorization
depending upon his request to view one or more of such encrypted pay channels of his
choice. The subscriber will pay for those pay channels which he or she has chosen to
view in such a system. The authorization is given and controlled by the Multi System
Operator (MSO) who owns the Conditional Access System in a Cable Television
Network. In this, he is often assisted by the Local Cable Operator. The words
“Conditional Access System” and “Addressable System” are quite often used
interchangeably. “Addressable system” signifies that a subscriber is identifiable. The
Multi System Operator and the broadcaster will know the exact number of subscribers of
a pay channel or a bouquet of pay channels and the amount that is due from that
subscriber.