Set-Top Box
Special digital set-top boxes are available for receiving digital television broadcasts on TV sets that do not have a built in digital tuner. In the case of direct broadcast satellite (mini-dish) systems, providers such as SES Astra, Dish Network, DirecTV, or Astro may use digital set-top boxes.
In the United Kingdom, digital set-top boxes (often referred to as digiboxes, after Sky's trademark for their unit) are usually for digital terrestrial television through services such as Freeview, a service operated by the Freeview Consortium, or through digital satellite, for example via British Sky Broadcasting or Freesat, and also with digital cable. They are used to access television as well as audio and interactive services through the "Red Button" promoted by broadcasters such as the BBC with BBC Red Button or Sky with Sky Active. Current Freeview set-top boxes and digital televisions are not capable of decoding the protocol DVB-T2 required for terrestrial High-definition in 2009, so viewers may need to purchase a new HD receiver.
In Australia, set-top boxes are the principal means of receiving digital terrestrial broadcasts, as comparably few television sets have in-built digital tuners. The Foxtel set-top boxes (including the Foxtel iQ unit) are also used to receive subscription television from Foxtel. For HDTV receiving, Foxtel is using Beyonwiz-manufactured media centers, which came to market in March 2007.
In the United States, deployment of a very basic coupon-eligible converter box had been supported through a $40 federal subsidy to encourage viewers of over-the-air television to adopt ATSC standards before the shutdown of full-power analog broadcasts. (This shutdown, originally planned for February 17, 2009, was re-scheduled for June 12, 2009, due to a concern that an insufficient number of affected viewers would be ready. The coupon programme ended in July 2009. Also, the transition of over-the-air channels from analog to digital should not be confused with similar digital conversions on cable networks.) These boxes were slow to be made available in Canada and Mexico, where broadcasters were not required to transition to digital television in 2009. While ATSC-capable tuners are beginning to appear in some new TVs and television-related products such as computer video capture cards, satellite receivers, and DVD recorders in these countries, many models do still require an external converter to receive DTV.
Globally, some boxes also have a built-in digital video recorder (or DVR), which often utilizes the electronic programme guide scheduling data and records content to an internal hard drive.
The above was sourced directly from Wikipedia on 31-08-10
