Businesses in the transmitters category supply, install, maintain or repair equipment that sends audio, video, data or control signals from one point to another. This may include radio and television broadcast transmitters, two-way radio base stations, wireless links, telemetry units and radio-frequency modules used in industrial, transport or communications systems. Some suppliers also provide associated aerials, feeders, amplifiers, power supplies, monitoring equipment and control software. Services can include selecting equipment for a particular coverage area or application, configuring frequencies and output settings, integrating transmitters with existing systems, and testing signal performance. Engineers may carry out installation, fault-finding, servicing and component repairs, as well as upgrades or replacement of older equipment.