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Digital Enhanced Cordless Telecommunications (Digital European Cordless Telecommunications), usually known by the acronym DECT, is a standard primarily used for creating cordless telephone systems. It originated in Europe, where it is the universal standard, replacing earlier cordless phone standards, such as 900 MHz CT1 and CT2. Beyond Europe, it has been adopted by Australia, and most countries in Asia and South America. North American adoption was delayed by United States radio frequency regulations. This forced development of a variation of DECT, called DECT 6.0, using a slightly different frequency range. The technology is nearly identical, but the frequency difference makes the technology incompatible with systems in other areas, even from the same manufacturer. DECT has almost universally replaced other standards in most countries where it is used, with the exception of North America. DECT is used primarily in home and small office systems, but is also available in many private branch exchange (PBX) systems for medium and large businesses. DECT can also be used for purposes other than cordless phones. Voice applications, such as baby monitors, are becoming common. Data applications also exist, but have been eclipsed by Wi-Fi. 3G and 4G cellular also competes with both DECT and Wi-Fi for both voice and data. DECT is also used in special applications, such as remote controls for industrial applications. In 2011, development of a low power variant (DECT ULE — ultra low energy) was initiated to take advantage of the existing data channels for DECT to address markets such as home automation, security and climate control. The low power variant enables this standard to be used in battery powered devices and for many devices in the home to be connected through a single control unit. The DECT standard includes a standardized interoperability profile for simple telephone capabilities, called GAP, which most manufacturers implement. GAP-conformance enables DECT handsets and bases from different manufacturers to interoperate at the most basic level of functionality, that of making and receiving calls. The standard also contains several other interoperability profiles, for data and for radio local-loop services. ==Application== The DECT standard fully specifies a means for a portable unit, such as a cordless telephone, to access a fixed telecoms network via radio. But, unlike the GSM standards, does not specify any internal aspects of the fixed network. Connectivity to the fixed network (that may be of many different kinds) is done through a base station or "Radio Fixed Part" to terminate the radio link, and a gateway to connect calls to the fixed network. In most cases the gateway connection is to the public switched telephone network or telephone jack, although connectivity with newer technologies such as Voice over IP has become available. There are also other devices such as some baby monitors utilizing DECT, and in these devices there is no gateway functionality. The DECT standard originally envisaged three major areas of application: * Domestic cordless telephony, using a single base station to connect one or more handsets to the public telecommunications network. * Enterprise premises cordless PABXs and wireless LANs, using many base stations for coverage. Calls continue as users move between different coverage cells, through a mechanism called handover. Calls can be both within the system and to the public telecommunications network. * Public access, using large numbers of base stations to provide high capacity building or urban area coverage as part of a public telecommunications network. Of these, the domestic application (cordless home telephones) has been extremely successful. The enterprise PABX market had some success, and all the major PABX vendors have offered DECT access options. The public access application did not succeed, since public cellular networks rapidly out-competed DECT by coupling their ubiquitous coverage with large increases in capacity and continuously falling costs. There has been only one major installation of DECT for public access: in early 1998 Telecom Italia launched a DECT network known as "Fido" after much regulatory delay, covering major cities in Italy.〔"Dect for Cordless Terminal Mobility" DECT Forum Newsletter 6 March 1998 ()〕 The service was promoted for only a few months and, having peaked at 142,000 subscribers, was shut down in 2001.〔("LA TELECOM SPEGNE "FIDO"" Il Messaggero 5 April 2000 )〕 DECT has also been used for Fixed Wireless Access as a substitute for copper pairs in the "last mile" in countries such as India and South Africa. By using directional antennas and sacrificing some traffic capacity, cell coverage could extend to over . In Europe the power limit laid down for use of the DECT spectrum (250 mW peak) was expressed as effective radiated power (ERP), rather than the more commonly used equivalent isotropically radiated power (EIRP), permitting the use of high-gain directional antennas to produce much higher EIRP and hence long ranges. The standard is also used in electronic cash terminals, traffic lights, and remote door openers. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Digital Enhanced Cordless Telecommunications」の詳細全文を読む スポンサード リンク
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