Digital Dictionary
Analogue signal
The broadcast signal which delivers just five TV channels (BBC1, BBC2, ITV, Channel 4 and Channel 5) to your set via an aerial.
Aerial upgrade
If your rooftop aerial is particularly old or if you have a set-top aerial, you might need to upgrade your aerial to one that can pick up the digital signal in order to receive digital terrestrial channels. Our install and repair network can help you with this.
Broadband
Gives fast access to the internet through your phone line and allows the phone to be used at the same time.
Common Interface
The Common Interface is an interconnect between a Digital TV or a set-top box, and a separate module. By far the most common module is the CAM (Conditional Access Module) which plugs into your Digital TV or set-top box, and allows you to insert a viewing card to watch certain subscription based TV services, for example Setanta Sports.
Coverage
The areas that can receive digital television. Not all the digital services are available everywhere in the UK. Use the Simplifydigital checker™ to find out which suppliers you can get at your address.
Cable TV
Cable television is just what it says it is - TV pictures and sound sent through underground cables to your home. One of the benefits of cable is that you can run home phone and broadband through it too. Virgin Media is the country's main cable-based digital service provider.
DAB
This stands for Digital Audio Broadcasting (DAB) - the DAB service is radio's equivalent of digital TV. It gives interference-free reception and has room for extra stations as well as all the standard channels. It's available across most of the country. You can receive DAB on personal, portable, tabletop or car radios. Digital radio stations are also received by digital TV set-top boxes and iDTVs (Integrated Digital Television). The digital switchover does not affect radio services.
Digital box
This is required for watching digital TV - it sits usually on top of your TV (see set-top box) and unscrambles digital signals before turning them back into sound and pictures.
Digital signal
Television images are sent as compressed data which is then unscrambled by a digital box. The signal is sent by cable, satellite or through the air to your aerial. After switchover you will only be able to receive a digital signal.
Digital switchover
The process of switching over the UK's current analogue television broadcasting system to digital, as well as ensuring that people have adapted or upgraded their televisions and recording equipment to receive digital TV. Find out more about the digital switchover.
DTT or DTTV
This means Digital Terrestrial Television - which is received via a rooftop aerial or set-top aerial. In the UK, this includes the Freeview service (which includes the traditional terrestrial channels - BBC One, BBC Two, ITV1, Channel 4 and Five) and for an additional monthly subscription, Top Up TV.
DTV
This is a common abbreviation for digital television.
Download limit
The maximum amount of data you can download per month from the internet. This includes songs, films and photos. Even reading emails and simply browsing the web will eat into this limit (but only by a tiny amount). If you or your family do a lot of downloading, then you will need a broadband service with a high download limit, or even unlimited downloads.
Download speed
This is a measurement of how fast data can arrive at your computer from the internet. The higher, the better (but it's usually more expensive).
EPG
Stands for Electronic Programme Guide - an on-screen listing of TV channels and programmes. You can use one to go to the programme you want, or to select something to record.
Fair usage policy
This is a policy used by some broadband suppliers to restrict the download speed of your connection at certain times of the day. Downloading very large amounts of data (films, for example) can slow down other people's broadband connections in your area. This is because many houses may share the same access point in the local telephone exchange. So in order to keep things fair the broadband supplier may restrict your usage at peak times.
Freeview
The main UK digital terrestrial television service, transmitted through an aerial. No subscription is required. See also Top Up TV.
FTA
Meaning Free-To-Air - or in other words a programme or service that you don't need a subscription to get.
HDTV
High Definition Television - a new technology that enables viewers to receive higher definition television pictures. HDTV has four times as many pixels (dots on the screen) as standard TV broadcasts, meaning a clearer picture and stunning detail on large-screen TVs.
iDTV
Integrated Digital Television - a TV with a built-in digital receiver which lets you receive Freeview channels through your aerial with no need for an additional digital box. It can refer to either a conventional cathode ray TV or one of the new flat panel TVs.
Interactive
This covers off all ways of interacting with a TV broadcast to get more information - a bit like an extension of the traditional Teletext service. For instance, you can select and watch a particular tennis match from a multi-screen selection, find out more information about a TV programme, cast a vote, or take part in a quiz. Accessing interactive services is usually done via the red button on your remote control.
Pay-per-view (PPV)
This is an additional one-off payment for a particular film or sporting event on satellite or cable/internet TV.
PVR
Stands for Personal Video Recorder. This is a device that records programmes to a hard drive (like a computer does) instead of to a video tape or disc. Programmes you want to record can be selected directly from the on-screen EPG. Many suppliers such as Sky and Virgin Media have PVR functionality integrated into their set-top boxes.
Platform
This is merely a way of delivering or receiving digital TV. Typical platforms are terrestrial, cable, satellite and the internet.
Rooftop aerial
A television aerial on the roof of your house.
Satellite
A satellite, as you're probably aware, is a space-enabled craft, the function of which is to bounce signals of all kinds around the globe, since the signal can't pass through it. Satellite TV is sent from the source to your dish this way.
Satellite dish
The dish on the side of people's houses that picks up programmes that have been transmitted and bounced off a satellite.
Satellite TV
Programmes received by the dish on the side of your house.
Set-top aerial
An aerial on top of your TV.
Set-top box
A kind of digital box that sits on top of your TV set, unscrambling the digital signal.
STB
Stands for Set-Top Box. See also digital box.
Switchover
See digital switchover.
Terrestrial TV
TV transmissions - analogue or digital - that are broadcast over the air directly to your TV aerial.
VCR
Video cassette recorder - the machine on which you have probably been recording and playing tapes for years. It can be used to record analogue or digital TV but records in fairly low analogue quality.
VOD
Stands for Video on Demand - which means you (usually) pay a fee for films and programmes you want to watch and then you can watch them when you want (and usually any number of times within a set time period - just like going to the video shop without leaving the house). There is usually a large library of films or programmes to choose from. Homechoice (currently in the London area and Stevenage) offers this service via broadband. A similar system, sometimes referred to as NVOD (near video on demand), is the 'Box Office' service offered by Sky where you can choose from a small number of films, though you may have to wait up to an hour for your film to start.
Widescreen
The ratio of the width to the height of the TV picture is 16 to 9 - often called 16:9 format. Nearly all major TV channels now make and broadcast their programmes in this widescreen format. Older programmes were in the narrower 4:3 format. If set up correctly, your TV and set-top box should display the picture on your screen in 16:9 or 4:3, as appropriate for the programme.
