Amazon.com and Best Buy are two of many retailers that sell analogue to digital conversion devices. These devices are required for analogue televisions to interpret the digital signal used by all broadcast television stations in the United States. Televisions that already have a built-in digital receiver do not require an analogue to digital converter.
Prices for analogue to digital converter boxes range from around $30 to $60 or more, as of 2015, and this price varies depending on the manufacturer of the device as well as the converter's extra features. All converters share the same core feature of allowing an analogue television to display broadcasts from a digital television signal.
The need for analogue to digital converter boxes arose in 2009, when the United States government finalized the shutdown of all analogue television broadcasts in the country. Television stations transitioned solely to digital transmissions, as was the requirement. Televisions manufactured after 2005 generally have a digital receiver built in due to government regulations, and thus these modern television sets have no need of a converter box. Older televisions that are either not high definition or were manufactured before 2005 are usually not able to interpret digital signals on their own and require a converter. These converters are not required for satellite and cable television broadcasts but are required for over-the-air broadcasts.