Set-top box

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.

As some 1960s-era 12-channel TV sets remained in use for many years, and Canada and Mexico 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.

Block conversion of the entire affected frequency band onto UHF, while less common, was used by some models to provide full VCR compatibility and the ability to drive multiple TV sets, albeit with a somewhat nonstandard channel numbering scheme.

In the United States, where the analogue shutdown was completed in 2009 for full-service broadcasters, a federal subsidy was offered for coupon-eligible converter boxes with deliberately limited capability which would restore signals lost to digital transition.

IRDs are capable of outputting uncompressed serial digital interface signals, unlike consumer STBs which usually do not, mostly because of copyright reasons.

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.

[8] UK-based Inview Technology has over 8 million STBs deployed in the UK for teletext and an original push VOD service for Top Up TV.

[9] In the US and Europe, telephone companies use IPTV (often on ADSL or optical fibre networks) as a means to compete with traditional local cable television monopolies.

This type of service is distinct from streaming television, which involves third-party content over the public Internet not controlled by the local system operator.

The parental lock or content filters allow users over 18 years old to block access to channels that are not appropriate for children, using a personal identification number.

As complexity and potential programming faults of the set-top box increase,[11] software such as MythTV, Select-TV and Microsoft's Media Center have developed features comparable to those of set-top boxes, ranging from basic DVR-like functionality to DVD copying, home automation, and housewide music or video playback.

Devices with the capabilities of computer terminals, such as the WebTV thin client, also fall into the grey area that could invite the term "NTB".

The use of digital 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 as DVB's Common Interface and ATSC's CableCARD therefore use a PCMCIA-like card inserted as part of the digital signal path as their alternative to a tuner-equipped set-top box.