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Circuit Board of the Set Top Box

D-View is a Set Top Box that enables viewers to access a wide range of services like Analog TV, Digital TV, Internet, Video on Demand, VoIP provided by Broadcasters. Broadcasters use Satellite, Terrestrial and Cable networks to transmit the TV signals and are increasingly demanding that viewers pay for their services and hence transmit scrambled signals.

For the decoding and viewing of free to air and scrambled signals therefore a Set Top Box is required at the TV user site. To address this requirement, C-DAC, Noida has designed a multi-purpose Set Top Box enabling decoding and decrypting of signals from all the three modes of transmission.

Digital Set Top Box has been categorized as:

  • D-View 1 - for Digital Terrestrial Transmission (DTT)
  • D-View 2 - for Digital to Home through Satellite

D-View 0 version is free to air, and would cost the viewers about Rs. 3000/-. The cost of other three versions of D-View range from Rs. 3000/- to Rs. 6000/-. The CAS is going to be implemented in four Metros w.e.f. september 1, 2003.


Set-top boxes (STB) act as a gateway between the user's television and telephone, satellite, terrestrial or cable feed (incoming signal). The STB receives encoded and/or compressed digital signals from the signal source (satellite, TV station, cable network and so on) and decodes (and/or decompresses) those signals, converting them into analog signals displayable on the television. Set-top boxes are usually embedded computers that process digital information. These typically have on-screen user interfaces that can be seen on the TV screen and interacted with, through the use of a Hand-held Interactive Keypad, which is little more than an advanced remote control. STBs also have facilities for upgrading software such as browsers and Electronic Program Guides (EPGs) hard-drives and smart card slots for purchases and eCommerce applications.

Common Interface describes hardware and software architecture for Conditional Access Systems whereby the generic "host" set-top box is not dedicated to one particular encryption system. Consumers can use detachable hardware, which allows them to receive encrypted services they pay subscription fee(s) for. The interface between host set-top box and the CI hardware is standardized (PCMCIA-Interface) so that the same set-top box can be used to handle a variety of encryption systems.

With a set-top box and a standard (analog) TV set, viewers with this service can access more channels, than what their standard tv allows. Also the STB enhances resolution.

A Conditional Access (CA) system comprises a combination of scrambling and encryption to prevent unauthorized reception. Encryption is the process of protecting the secret keys that are transmitted with a scrambled signal to enable the descrambler to work. The scrambler key, called the control word must, of course, be sent to the receiver in encrypted form as an entitlement control message (ECM). The CA subsystem in the receiver will decrypt the control word only when authorized to do so, that authority is sent to the receiver in the form of an Entitlement Management Message (EMM). This layered approach is fundamental to all proprietary CA systems in use today. This technique is primarily used in a Digital Set Top Box.

C-DAC (Noida) developed the Digital STB, capable of receiving signals through DTT, DTH and Cable medium. The costs of these STB are

1. DTT Rs. 3500/-

2. DTH Rs. 4000/-

3. Cable Rs. 6000/-

The Cable Set Top Box is available with Conditional Access System and Smart Card Compatibility.