Modern signallers are responsible for the battlefield voice and data communication and information technology infrastructure or in common English terms, they may carry a backpack radio transceiver used to communicate to forward operating bases (large and small outposts for the military), using a variety of media. All types of wire (line), satellite and ionospheric radio communication are employed. These include common radio systems such as HF/VHF radio and UHF/SHF radio (operated in line of sight, for example). Cellular radio and telephone systems such as TETRA are also becoming common.