Editing Set-top box (section)

===Cable converter===
{{main|Cable converter box}}
[[File:HK Cable TV Settop Box 2002.jpg|left|thumb|An older digital cable TV set-top box]]
[[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&nbsp;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 VHF [[Pan-American television frequencies|channel 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 a [[cable converter box]] was needed to receive the additional [[Analog television|analogue]] [[Cable television|cable]] [[television channel|TV channels]] and transpose or convert the selected channel to analogue [[radio frequency]] (RF) for viewing on a regular TV set on a single channel, usually [[very high frequency|VHF]] channel 3 or 4. The box allowed an analogue non–cable-ready [[television]] 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 selling [[pay television|premium television]] (aka [[pay-per-view]]). Several years later and slowly marketed, the advent of [[digital cable]] continued and increased the need for various forms of these devices. [[Low-noise block downconverter|Block conversion]] of the entire affected frequency band onto [[ultra high frequency|UHF]], while less common, was used by some models to provide full [[videocassette recorder|VCR]] 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, although [[cable converter box]]es continue to be used to [[scrambler|descramble]] premium cable channels according to carrier-controlled access restrictions, and to receive digital cable channels, along with using interactive services like [[video on demand]], pay per view, and [[home shopping]] through television.