The digital broadcasting technology adopted in the UK is the DVB-T system (Digital Video Broadcasting – Terrestrial) carrying compressed digital audio, video and other data in a combined transport stream, using modulation. A total of eight national and one local 'multiplexes' are broadcast in the UK, guaranteed to reach over 90% of the country. Three of the multiplexes, carrying the free public service channels operated by the BBC, ITV, Channel 4, S4C and Channel 5, are guaranteed wider coverage still, reaching 98.5% of the country including areas dependent on low-power local relays.