Contrast with pay tv . The number of times a wave of electro-magnetic radiation, such as a radio wave, arcs or cycles per second. The frequency of a wave determines its position within the electro-magnetic spectrum . A band of frequencies used to transmit a radio or television service. With an analogue transmission system, one frequency channel is needed for each service.
Digital transmission allows more than one service to be carried on a single frequency channel.
Satellites in this orbit are synchronised with the rotation of the earth and so appear stationary relative to the earth's surface. This contracts with satellites in low earth orbit . Linking together of two disparate networks, for example so that parties connected to one network can communicate with parties connected to the other. Companies that, for a monthly or annual fee, will provide access to the Internet via the standard telephone system, or via faster ISDN or leased telecommunications lines. A set of standards for digital telecommunications designed to transform analogue public telecommunications networks into digital networks.