Aset-top box (STB), also known as acable box,receiver, or simplybox, and historicallytelevision decoder or aconverter,[1] is aninformation appliance device that generally contains aTV tuner input and displays output to atelevision set, turning the sourcesignal intocontent in a form that can then be displayed on the television screen or otherdisplay device. It is designed to be placed alongside or "on top" (hence the name) of a television set.[2]
Set-top boxes are used incable television,satellite television,terrestrial television andInternet Protocol television systems, as well as other uses such asdigital media players ("streaming boxes"). Alternatives to set-top boxes are the smallerdongles, and television sets with built-in TV tuners.
The signal source might be anEthernet cable, asatellite dish, acoaxial cable (seecable television), atelephone line (includingDSL connections),broadband over power lines (BPL), or even an ordinaryVHF orUHFantenna. Content, in this context, could mean any or all ofvideo,audio,Internetweb pages,interactivevideo games, or other possibilities. Satellite and microwave-based services also require specific external receiver hardware, so the use of set-top boxes of various formats has never completely disappeared. Set-top boxes can also enhance source signal quality.
Before theAll-Channel Receiver Act of 1962 required UStelevision receivers to be able to tune the entireVHF andUHF range (which inNorth America wasNTSC-M channels2 through 83 on 54 to 890 MHz), a set-top box known as a UHF converter would be installed at the receiver to shift a portion of the UHF-TV spectrum onto low-VHF channels for viewing. As some 1960s-era 12-channel TV sets remained in use for many years, andCanada andMexico were slower than the US to require UHF tuners to be factory-installed in new TVs, a market for these converters continued to exist for much of the 1970s.
Cable television represented a possible alternative to deployment of UHF converters as broadcasts could be frequency-shifted to VHF channels at the cable head-end instead of the final viewing location. However, most cable systems could not accommodate the full 54-to-890 MHz VHF/UHF frequency range and the twelve channels of VHF space were quickly exhausted on most systems. Adding any additional channels therefore needed to be done by inserting the extra signals into cable systems on nonstandard frequencies, typically either below VHFchannel 7 (midband) or directly above VHF channel 13 (superband).
These frequencies corresponded to non-television services (such as two-way radio) over the air and were therefore not on standard TV receivers. Before cable-ready TV sets became common in the late 1980s, an electronic tuning device called acable converter box was needed to receive the additionalanaloguecableTV channels and transpose or convert the selected channel to analogueradio frequency (RF) for viewing on a regular TV set on a single channel, usuallyVHF channel 3 or 4. The box allowed an analogue non–cable-readytelevision set to receive analogue encrypted cable channels and was a prototype topology for later date digital encryption devices. Newer televisions were then converted to be analogue cypher cable-ready, with the standard converter built-in for sellingpremium television (akapay-per-view). Several years later and slowly marketed, the advent ofdigital cable continued and increased the need for various forms of these devices.Block conversion of the entire affected frequency band ontoUHF, while less common, was used by some models to provide fullVCR compatibility and the ability to drive multiple TV sets, albeit with a somewhat nonstandard channel numbering scheme.
Newer television receivers greatly reduced the need for external set-top boxes, althoughcable converter boxes continue to be used todescramble premium cable channels according to carrier-controlled access restrictions, and to receive digital cable channels, along with using interactive services likevideo on demand, pay per view, andhome shopping through television.
Set-top boxes were also made to enableclosed captioning on older sets in North America, before this became a mandated inclusion in newtelevision sets. Some have also been produced to mute theaudio (or replace it with noise) whenprofanity is detected in the captioning, where the offensive word is also blocked. Some also include aV-chip that allows only programs of sometelevision content rating systems. A function that limits children's time watching TV or playingvideo games may also be built in, though some work on main electricity rather than the video signal.
Thetransition todigital terrestrial television after the turn of the millennium left many existingtelevision receivers unable to tune and display the new signal directly. In the United States, where theanalogue shutdown was completed in 2009 for full-service broadcasters, a federal subsidy was offered forcoupon-eligible converter boxes with deliberately limited capability which would restore signals lost to digital transition.
Professional set-top boxes are referred to as IRDs orintegrated receiver/decoders in the professional broadcast audio/video industry. They are designed for more robust field handling andrack mounting environments. IRDs are capable of outputting uncompressedserial digital interface signals, unlike consumer STBs which usually do not, mostly because of copyright reasons.
.jpg)
Hybrid set-top boxes, such as those used forSmart TV programming, enable viewers to access multiple TV delivery methods (including terrestrial, cable, internet, and satellite);[3] like IPTV boxes, they includevideo on demand,time-shifting TV, Internet applications,videotelephony, surveillance, gaming, shopping, TV-centricelectronic program guides, and e-government. By integrating varying delivery streams, hybrids (sometimes known as "TV-centric"[4]) enable pay-TV operators more flexible application deployment, which decreases the cost of launching new services, increases speed to market, and limits disruption for consumers.[5]
As examples,Hybrid Broadcast Broadband TV (HbbTV) set-top boxes allow traditional TV broadcasts, whether fromterrestrial (DTT), satellite, or cable providers, to be brought together with video delivered over the Internet and personal multimedia content.Advanced Digital Broadcast (ADB) launched its first hybrid DTT/IPTV set-top box in 2005,[6] which providedTelefónica with the digital TV platform for itsMovistar TV service by the end of that year.[7] In 2009, ADB provided Europe's firstthree-way hybrid digital TV platform to Polish digital satellite operatorn, which enables subscribers to view integrated content whether delivered via satellite, terrestrial, or internet.[8]
UK-basedInview Technology has over 8 million STBs deployed in the UK forteletext and an original pushVOD service for Top Up TV.
InIPTV networks, the set-top box is a small computer providing two-way communications on anIPnetwork and decoding the videostreaming media. IP set-top boxes have a built-inhome network interface that can beEthernet, Wireless (802.11 g,n,ac), or one of the existing wire home networking technologies such asHomePNA or theITU-TG.hn standard, which provides a way to create a high-speed (up to 1 Gbit/s)local area network using existing home wiring (power lines, phone lines, andcoaxial cables).[9]
In the US and Europe, telephone companies use IPTV (often onADSL oroptical fibre networks) as a means to compete with traditional localcable television monopolies.
This type of service is distinct fromstreaming television, which involves third-party content over the public Internet not controlled by the local system operator.
Electronic program guides and interactive program guides provide users of television, radio, and other media applications with continuously updated menus displayingbroadcast programming or scheduling information for current and upcoming programming. Some guides, such asITV, also feature backward scrolling to promote their catch-up content.[10]
This feature allows the user to choose preferred channels, making them easier and quicker to access; this is handy with the wide range of digital channels on offer. The concept of favourite channels is superficially similar to that of the "bookmark" function offered in many web browsers.
Thetimer allows the user to program and enable the box to switch between channels at certain times: this is handy to record from more than one channel while the user is out. The user still needs to program the VCR or DVD recorder.
Some models have controls on the box, as well as on theremote control. This is useful should the user lose the remote or if the batteries age.
Someremote controls can also control some basic functions of various brands of TVs. This allows the user to use just one remote to turn the TV on and off, adjust volume, or switch between digital and analogue TV channels or betweenterrestrial andinternet channels.
Theparental lock orcontent filters allow users over 18 years old to block access to channels that are not appropriate for children, using apersonal identification number. Some boxes simply block all channels, while others allow the user to restrict access to chosen channels not suitable for children below certain ages.
As complexity and potential programming faults of the set-top box increase,[11] software such asMythTV,Select-TV andMicrosoft'sMedia Center have developed features comparable to those of set-top boxes, ranging from basic DVR-like functionality toDVD copying,home automation, and housewide music or video playback.
Almost all modern set-top boxes feature automaticfirmware update processes. The firmware update is typically provided by the service provider.
With the advent offlat-panel televisions, set-top boxes are now deeper in profile than the tops of most modern TV sets. Because of this, set-top boxes are often placed beneath televisions, and the term set-top box has become something of amisnomer, possibly helping the adoption of the termdigibox. Additionally, newer set-top boxes that sit at the edge of IP-based distribution networks are often called net-top boxes or NTBs, to differentiate between IP and RF inputs. The Roku LT is around the size of a pack of cards and delivers Smart TV to conventional sets.[12]
The distinction between external tuner ordemodulator boxes (traditionally considered to be "set-top boxes") and storage devices (such as VCR, DVD, or disc-based PVR units) is also blurred by the increasing deployment of satellite and cable tuner boxes with ahard disk,network orUSB interfaces built-in.
Devices with the capabilities ofcomputer terminals, such as theWebTVthin client, also fall into the grey area that could invite the term "NTB".
In Europe, a set-top box does not necessarily contain atuner of its own. A box connected to a television (or VCR)SCART connector is fed with thebaseband television signal from the set's tuner, and can have the television display the returned processed signal instead.
This SCART feature had been used for connection to analogue decoding equipment bypay-TV operators in Europe, and in the past, it was used for connection to teletext equipment before the decoders became built-in. The outgoing signal could be of the same nature as the incoming signal, orRGBcomponent video, or even an "insert" over the original signal, due to the "fast switching" feature of SCART.
In case of analogue pay-TV, this approach avoided the need for a secondremote control. The use ofdigital television signals in more modern pay-TV schemes requires that decoding take place before the digital-to-analogue conversion step, rendering the video outputs of an analogue SCART connector no longer suitable for interconnection to decryption hardware. Standards such asDVB'sCommon Interface andATSC'sCableCARD therefore use aPCMCIA-like card inserted as part of the digital signal path as their alternative to a tuner-equipped set-top box.
According to theLos Angeles Times, the cost to a cable provider in the United States for a set-top box is between $150 for a basic box to $250 for a more sophisticated box. In 2016, the averagepay-TV subscriber paid $231 per year to lease their set-top box from a cable service provider.[13]
In June 2011, a report from the American National Resources Defense Council brought attention to theenergy efficiency of set-top boxes,[14] and theUnited States Department of Energy announced plans to consider the adoption of energy efficiency standards for set-top boxes.[15] In November 2011, the National Cable & Telecommunications Association announced a new energy efficiency initiative that commits the largest American cable operators to the purchase of set-top boxes that meetEnergy Star standards and the development ofsleep modes that will use less energy when the set-top box is not being used to watch or record video.[16]
