A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related emergencies are detected. These alarms may be activated automatically from smoke detectors and heat detectors or may also be activated via manual fire alarm activation devices such as manual call points or pull stations. Alarms can be either motorized bells or wall mountable sounders or horns. They can also be speaker strobes which sound an alarm, followed by a voice evacuation message which warns people inside the building not to use the elevators. Fire alarm sounders can be set to certain frequencies and different tones including low, medium, and high, depending on the country and manufacturer of the device. Most fire alarm systems in Europe sound like a siren with alternating frequencies. Fire alarm electronic devices are known as horns in the United States and Canada and can be either continuous or set to different codes. Fire alarm warning devices can also be set to different volume levels.
Devon(/ˈdɛvən/, also known asDevonshire) is acountyofEngland, reaching from theBristol Channelin the north to theEnglish Channelin the south. It is part ofSouth West England, bounded byCornwallto the west,Somersetto the north-east andDorsetto the east. The city ofExeteris thecounty town. The county includes the districts ofEast Devon,Mid Devon,North Devon,South Hams,Teignbridge,TorridgeandWest Devon.PlymouthandTorbayare each geographically part of Devon, but are administered asunitary authorities.Combined as aceremonial county, Devon's area is 6,707 km2(2,590 square miles)and its population is about 1.1 million.
Devon derives its name fromDumnonia(the shift frommtovis a typicalCeltic consonant shift). During theBritish Iron Age,Roman Britainand theearly Middle Ages, this was the homeland of theDumnoniiBrittonicCelts. TheAnglo-Saxon settlement of Britainresulted in the partial assimilation of Dumnonia into theKingdom of Wessexduring the eighth and ninth centuries. The western boundary with Cornwall was set at theRiver TamarbyKing Æthelstanin 936. Devon was later constituted as ashireof theKingdom of England.
The north and south coasts of Devon each have both cliffs and sandy shores, and the county'sbayscontainseaside resorts,fishing townsandports. The inland terrain is rural, generally hilly and has a lower population density than many other parts of England.Dartmooris the largest open space in southern England, at 954 km2(368 square miles);itsmoorlandextends across a large expanse ofgranitebedrock. To the north of Dartmoor are theCulm MeasuresandExmoor. In the valleys and lowlands of south and east Devon the soil is more fertile, drained by rivers including theExe, theCulm, theTeign, theDartand theOtter.
As well as agriculture, much of theeconomy of Devonis based ontourism. The comparatively mild climate, coastline and landscape make Devon a destination forrecreation and leisure in England. Visitors are particularly attracted to the Dartmoor and Exmoornational parks; its coasts, including the resort towns along the south coast known collectively as theEnglish Riviera; theJurassic CoastandNorth Devon's UNESCO Biosphere Reserve; and the countryside including theCornwall and West Devon Mining Landscape.