Aerial group - the letter code (A, B, CD, E, K or W) which identifies which UHF channels that aerial can receive.
ATT - Analogue Terrestrial Television. Older system of broadcasting carrying five channels in the UK.
BBC - Broadcaster that owns multiplexes 1 and B as well as renting space on A and D. Co-founder and operator of Freeview.
Box with a slot - set-top box that has a viewing card reader.
CAM - piece of hardware that a viewing card may need to be inserted into before itself is inserted into an IDTV.
Crown Castle - company that set up Freeview with the BBC. Owners of multiplexes C and D.
Digital 3&4 - a consortium made up of the ITV franchise holders and Channel 4 to operate multiplex 2.
Download - Software update for equipment broadcast along with the TV signal, usually on multiplex 1, and usually to add new features or fix bugs.
DTG - Digital TV Group: the industry association for digital television, which oversees technical specifications and standards.
DTT - Digital Terrestrial Television, the technical name for digital TV through an aerial.
DVB-T - Digital Video Broadcasting - Terrestrial, another name for DTT.
EPG - Electronic Programme Guide, system of showing what programmes are on each channel. Some equipment only shows "now and next" info, others can give up to 8 days´ programmes.
Freeview - the brand name given to the package of free channels available on DTT.
IDTV - Integrated Digital Television, a TV set with a digital tuner built in, so a separate set-top box is not needed.
ITC - Independant Television Commission, former regulatory body that awarded licences to multiplex operators. Since amalgamated into OfCom.
ITV Digital - company that operated the DTT service before it went into administration and closed down in 2002.
ITV multiplex - common name given to multiplex 2, because it has the ITV channels on it.
LCN - Logical Channel Number, the number you enter on your remote control to tune to a particular channel. LCN is often used to avoid confusion with UHF channel numbers.
MHEG - system for displaying text and graphics on interactive services and radio channels.
Multiplex - a group of channels broadcast together as one signal. There are 6 DTT multiplexes in the UK, called 1, 2, A, B, C and D.
Mux - short for multiplex.
NTL - company that owns and maintains many transmitters.
OfCom - Office of Communications, body that regulates the industry, took over the ITC.
Out of band multiplex - a multiplex that cannot be picked up by aerials that point to that transmitter for ATT, because they are of a certain aerial group. Usually, to receive an out of band multiplex an aerial upgrade is required.
RF - method of connecting equipment together via aerial cable. A box with RF loop will pass ATT channels from its input to its output so they can still be tuned to on a TV set. A box with RF mod (modulator) will output the digital broadcast it´s tuned to on an analogue UHF channel for TV sets without a SCART.
RF loopthrough - a box with RF loopthrough simply passes the analogue signal through the box without adding digital signal to it on a UHF frequency. You can only watch the digital signal from this type of box via SCART.
SCART - method of connecting audio-visual equipment eg set-top box to TV set, with better picture quality than RF aerial cable.
SDN - S4C Digital Networks, owned by ITV plc, operator of multiplex A, sometimes referred to as the SDN multiplex.
Set-top box - equipment that´s connected between aerial and TV set, converts digital signal into a´log signal that the TV can tune into.
Sky multiplex - multiplex C, called the Sky multiplex because it has the Sky channels on it.
STB - abbreviation of Set-top Box.
Timeshared channels - channels that only broadcast for part of the day to make way for other service(s) when it is off-air e.g. BBC Three and CBBC, or UKTV Bright Ideas and FTN.
Top Up TV - company that provides extra subscription channels on DTT via a viewing card.
UHF - Ultra High Frequency, the part of the spectrum that DTT and ATT are broadcast on, split into the UHF channels from 21 to 69.
Viewing card - provided by Top Up TV to allow access to subscribed channels.
Wideband aerial - aerial of group W, that can pick up broadcasts on all UHF channels 21-69.
