Cable converter box

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A cable converter box or television converter box is an set-top electronic tuning device that transposes/converts any of the available channels from a cable television service to an analog RF signal on a single channel, usually VHF channel 3 or 4. The device allows a television set that is not “cable ready” to receive cable channels. While later televisions were "cable ready" with a standard converter built-in, the existence of premium television (aka pay per view) and the advent of digital cable have continued the need for various forms of these devices for cable television reception. While not an explicit part of signal conversion, many cable converter boxes include forms of descrambling to manage carrier-controlled access restriction to various channels.

Cable-ready televisions and other cable-aware A/V devices such as video recorders can similarly convert cable channels to a regular television, but these do not include advanced capabilities such as descrambling or digital downconversion.

The task of a cable box is to convert a television channel from those transmitted over the CATV wire

The basic converter box is passive and does not communicate back to the carrier. It simply tunes to one of the channels being transmitted together over the wire and re-transmits it to a television or other video device on a standard broadcast frequency (usually a customer-selected, locally-unused frequency between VHF 2 and 4). Like other set-top boxes, converter boxes usually provide multiple options for the output channel (either 2/3 or 3/4) so that the same box can be used, with simple configuration, in multiple television markets. Despite not having a broadcast reception television antenna, a strong local television station can cause interference with the TV's reception of the cable converter's signal, resulting in undesired static or ghosting.

Later cable boxes became addressable, allowing the carrier to independently identify one cable box from another. In early systems, this permitted the carrier to send instructions to the boxes by addressing them over the wire. This allowed customers to subscribe to premium television and pay-per-view. More recent cable boxes, particularly those for digital cable, engage in two-way communication with the carrier central office, allowing for more advanced and interactive features.

Typically, a cable converter box has two coaxial F-type female connectors; one "Cable In" for a coaxial cable from the wall jack (containing the CATV signal), and one "TV Out" connected to the television where an antenna or other RF device (such as a VCR) would be connected. Newer cable boxes also tend to come standard with RCA jacks for composite video and stereo audio. More advanced devices may have s-video and/or HDMI outputs.

In early days, before televisions came standard with 300Ω coaxial antenna connectors, cable boxes came with adapters that would allow the coaxial cable connect to the 75Ω twin lead screws used with traditional antennas.

1 Descrambler
2 Combination Converter/Descrambler
3 Addressable Converter/Descrambler
4 Digital Converter
5 Cable terms: Basic, Premium, Pay Per View Services
6 References
7 See also

[edit] Descrambler

A Descrambler is a device that unscrambles the encoded signal and restores the picture and sound of a scrambled channel. A descrambler must be used with a converter to be able to descramble all the premium and pay-per-view channels of a cable television system. When a descrambler is added in series to the converter it decodes or descrambles the encrypted signal and allows : local broadcast channels, basic cable channels, authorized premium channels, pay-per-view (PPV), and video on demand (VOD) services to be viewed.

When a descrambler is added to the converter in the same chassis, it is referred to as a converter/descrambler or sometimes a combination unit.

[edit] Combination Converter/Descrambler

A Combination Converter/Descrambler is generally called a set-top box or "STB"; it is a single (one-piece) system installed in a single cabinet and represents a single component that is capable of descrambling premium services, like HBO or Showtime, pay-per-view cable channels., video on demand, games or other specialty pay services, and transposes the cable signal for RF output on channel 3 or 4. This unit contains a converter and a descrambler, enclosed in a common box and outputs the signal directly to your TV, VCR, DVR, PC, DVD or video projector.

[edit] Addressable Converter/Descrambler

An Addressable Converter/Descrambler is one that can be controlled by the local cable company. The addressable converter/descrambler is the customer-premises equipment (CPE) part of an addressable system. Addressability is the process by which (optionally encrypted) messages are sent via the cable system. The cable company can "address" the a particular customer's CPE unit to command it to activate or deactivate the descrambling of selected premium or pay-per view channels. The system can also send messages. This function affords the cable company the ability to add or delete descrambling on the channels that come in through the coaxial cable line. It also allows them to remotely disable the box, for reasons such as non-payment of the cable bill or theft of the unit itself. Such commands are referred to as bullets and are a transmitted message which effects the cable box program effectively disabling or "killing" it. "Bullets" do not affect the electronics inside converters or descramblers, only the programming. Non-addressable boxes are “bullet proof” as they are unable to detect such messages.

[edit] Digital Converter

Digital television allows higher quality and quantity of cable TV signals. Digital transmission is compressed and allows a much greater capacity than analog signals it almost completely eliminates interference, which has always been a hindrance to the cable TV industry. Digital converters have the same purpose as analog ones but are able to receive digital cable signals. With more data than analog in the same bandwidth, the system delivers superior picture and sound quality.

[edit] Cable terms: Basic, Premium, Pay Per View Services

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Non-cable ready television sets: Older televisions (i.e. with a rotary knob) with no coaxial cable F connector; a cable converter box or a cable ready VCR is necessary.

Cable ready television sets: Have a coaxial cable, F connectors. One end connects to the cable/antenna/VHF jack on the back of the television set, the other end connects to the wall CATV outlet. Once the television is connected to the cable to the wall CATV outlet, the television will need to be programmed to receive the cable channels. The instruction manual that came with the television should have instructions on how to program cable channels.

Basic cable service: The least expensive cable service provided by cable companies to their customers. This service usually includes local TV channels.

Premium cable service: Additional programming service provided by the cable company to subscribing customers. The extra fee for such additional service may be based on a per channel, per group of channels, or on any other combination of channels. Some of the premium channels include: Disney, Showtime, HBO, Playboy, etc.

Pay per view: Selected channels that offer movies and special events such as sports or adult entertainment, for an additional fee, on a per movie or per program basis. A special "addressable" converter is furnished by the cable company to subscribers of this service. Through the use of special equipment, the cable company can "address" the customer's cable box to descramble the program for which the fee was paid.