Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point-to-point (P2P), point-to-multipoint (P2MP), or mesh wired or wireless links. Even though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that require additional security or ongoing monitoring (Videotelephony is seldom called "CCTV").
Surveillance of the public using CCTV is common in many areas around the world. Video surveillance has generated significant debate about balancing its use with individuals' right to privacy even when in public.
In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, especially if the environments observed are dangerous or inaccessible to humans. CCTV systems may operate continuously or only as required to monitor a particular event. A more advanced form of CCTV, using digital video recorders (DVRs), provides recording for possibly many years, with a variety of quality and performance options and extra features (such as motion detection and email alerts). More recently, decentralized IP cameras, perhaps equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for completely stand-alone operation.
By one estimate, there will be approximately 1 billion surveillance cameras in use worldwide by 2021.[needs update] About 65% of these cameras are installed in Asia. The growth of CCTV has been slowing in recent years.[unreliable source?] The deployment of this technology has facilitated significant growth in state surveillance, a substantial rise in the methods of advanced social monitoring and control, and a host of crime prevention measures throughout the world.
A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms.
Some alarm systems serve a single purpose of burglary protection; combination systems provide fire and intrusion protection. Intrusion-alarm systems are combined with closed-circuit television surveillance (CCTV) systems to record intruders' activities and interface to access control systems for electrically locked doors. There are many types of security systems. Homeowners typically have small, self-contained noisemakers. These devices can also be complicated, multirole systems with computer monitoring and control. It may even include a two-way voice which allows communication between the panel and monitoring station.
Dorchester (/ˈdɔːrtʃɛstər/ DOR-ches-tər) is the county town of Dorset, England. It is situated between Poole and Bridport on the A35 trunk route. A historic market town, Dorchester is on the banks of the River Frome to the south of the Dorset Downs and north of the South Dorset Ridgeway that separates the area from Weymouth, 7 miles (11 km) to the south. The civil parish includes the small town of Poundbury and the suburb of Fordington.
The area around the town was first settled in prehistoric times. The Romans established a garrison there after defeating the Durotriges tribe, calling the settlement that grew up nearby Durnovaria; they built an aqueduct to supply water and an amphitheatre on an ancient British earthwork. After the departure of the Romans, the town diminished in significance, but during the medieval period became an important commercial and political centre. It was the site of the "Bloody Assizes" presided over by Judge Jeffreys after the Monmouth Rebellion, and later the trial of the Tolpuddle Martyrs.
In the 2011 census, the population of Dorchester was 19,060, with further people coming from surrounding areas to work in the town which has six industrial estates. The Brewery Square redevelopment project is taking place in phases, with other development projects planned. The town has a land-based college, Kingston Maurward College, The Thomas Hardye School, three middle schools and thirteen first schools. The Dorset County Hospital offers an accident and emergency service, and the town is served by two railway stations. Through vehicular traffic is routed round the town by means of a bypass. The town has a football club and a rugby union club, several museums and the biannual Dorchester Festival. It is twinned with three towns in Europe. As well as having many listed buildings, a number of notable people have been associated with the town. It was for many years the home and inspiration of the author Thomas Hardy, whose novel The Mayor of Casterbridge uses a fictionalised version of Dorchester as its setting.