DECT is a Pan-European digital cordless telephone standard for mobile communications via radio telephone; the acronym DECT stands for Digital European Cordless Telecommunications. DECT has been developed within the European Telecommunications Standardization Institute (ETSI), and as such is a standard intended for use throughout Europe. DECT focuses on defining a radio interface that can provide commonality of operation for cordless telecommunications between European countries. |
The implementation is a TDMA/TDD/MC (Time Division Multiple Access/Time Division Duplex/Multiple Carrier) system operation just below 2 GHz. An important feature of the DECT frame structure is the ability to employ multiple time slots to support higher data rate links, for example ISDN services. Occupied DECT timeslots can change carrier frequency within a single frame, providing added system flexibility. These features provide some advantages over the CT2 cordless standard.
DECT has a provision for a smart card called the DECT Authentication Module, or DAM, which corresponds to the GSM SIMS. The DAM has the same physical size and uses the same physical interface, as well as the same principal logic structure, as the GSM SIMS. The DAM is presently designed to be a multifunctionality card, and can contain more than one identity. DECT portables can, but need not necessarily, make use of the DAM for authentication.
DECT proposes to offer a range of services in the areas of business use, public access, residential use, and local loop replacement.
The benefit in business environments is new services with mobility. DECT's full ISDN compatibility facilitates this. DECT may be used either with a PABX or as a stand-alone system. The structure and features of DECT were created with business applications in mind, and include the ability to handle both speech and high density data. Although the most obvious business application is a cordless phone that can be used everywhere, some of the first DECT appliances to reach the market are for data transmission only.
For public access applications, DECT is superior to "tethered" Telepoint systems which use radio links in fixed telephone booths in that it is designed to handle both handover and roaming. Thus DECT Telepoints may occur in semi-private environments such as airports, airplanes, and shops as well as in the public street. Such links could be used for either voice or data (e.g. remotely connecting a lap-top computer to a home-based server). Another possibility is that locations such as retail stores that have installed DECT for their own use might open the use of the system for their customer's use as well - the customer would then be using DECT as access to the public network.
For residential applications, DECT offers a replacement to existing CT0 and CT1 equipment, presently used extensively throughout Europe. Advantages include a higher performance digital system and the convenience of a Pan-European standard.
Replacement of the Local Loop with a cordless telecommunications device such as a DECT radio link has similarities to the Telepoint application, but uses a network architecture similar to that found in the business application. Initially a means for network operators to gain efficiency through flexible structure, it also offers the possibility of later adding mobility. Cordless Local Loop (CLL) and Neighborhood Access (NA; sometimes called Neighborhood Telepoint) are similar, both aimed at replacing the last piece of cabling to the subscriber with a radio link. Pure CLL only replaces the cable, and does not effect the house installation. NA adds mobility within a limited area, such as the residential tract. Thus the physical implementation can vary between these two: CLL makes extensive use of directional antennas, whereas NA uses higher radiated power and / or more base stations.
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