TAILIEUCHUNG - Điện thoại di động mạng lưới Radio P9

Besides cellular mobile radio networks that are primarily envisaged for use outdoors, systems that have been specifically designed for use in buildings are also important. In recent years cordless telephones with a range of a few hundred metres have become increasingly popular in private households. There is (along with CT2/CAI) a digital alternative to these analogue devices that offers better voice quality and a greater security against eavesdropping, as well as other advantages: the DECT system | Mobile Radio Networks Networking and Protocols. Bernhard H. Walke Copyright 1999 John Wiley Sons Ltd ISBNs 0-471-97595-8 Hardback 0-470-84193-1 Electronic 9 DECT Besides cellular mobile radio networks that are primarily envisaged for use outdoors systems that have been specifically designed for use in buildings are also important. In recent years cordless telephones with a range of a few hundred metres have become increasingly popular in private households. There is along with CT2 CAI a digital alternative to these analogue devices that offers better voice quality and a greater security against eavesdropping as well as other advantages the DECT system. The abbreviation DECT originally stood for Digital European Cordless Telecommunications but to underline its claim of being a worldwide standard for cordless telephony DECT today stands for Digital Enhanced Cordless Telecommunications. This standard was specified by the European Telecommunications Standards Institute ETSI in 1992. A DECT network is a microcellular digital mobile radio network for high user density and primarily for use inside buildings. However an outdoor application is also possible. DECT systems allow complete cordless private branch exchanges to be set up in office buildings. Calls can be made over the normal subscriber line as well as between mobile stations through the DECT base station subsystem. When a staff member leaves his office he usually can no longer be reached for incoming calls over a wireline telephone connection although he may only be located in another part of the building. But if he uses a DECT terminal he can continue to be reached under his normal telephone number wherever he may be anywhere on the premises. To enable users to continue to receive calls after they have left the DECT coverage area ETSI specified an interface between GSM and DECT see Section . The DECT standard permits the transmission of voice and data signals. Consequently cordless data networks can also be

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