Subscriber authentication key of UAK (User Authentication Key) up to 128 bits long. UAK is the unique size containing in registration data of the user. It is stored in ROM of subscriber station or in the DAM card (DECT Authentication Module).
The indirect method in one case means a combination of two procedures - authentications the EXPERT and enciphering of data (as enciphering of information requires knowledge of an authentication key To), and in other - enciphering of data with use of a static key of SCK (Static Cipher Key) known to both stations.
Profiles of appendices define the additional specification of a legal stack of the DECT for concrete appendices. Though the basic DECT standard defined in ETS 300 175 is provided by possibility of realization of full range of services, a main objective of profiles of the appendix — to provide compatibility of the equipment of different producers. There are following main DECT profiles determined by ETSI:
In general it is possible to tell that the RLL systems conforming to the DECT standard it is better than others are suitable for work in the conditions of the average or high density of subscribers - either in the cities, or in rural areas where the number of subscribers can be and it is small, however density of their placement is quite high. These systems will suit also subscribers who now or in the future will want to use communication lines for data transmission or for work with the ISDN network.
Though the DECT standard defines the technology of a radio access providing mobility in it network aspects of system are not considered. Therefore the DECT technology can be used for access to any networks. GIP describes a way of connection of the DECT networks to the GSM network. Such access is provided with the GSM network interface A (to MSC). Thus the GSM network perceives the DECT as system of base stations (BSC).
The registration is a process thanks to which the system allows the specific EXPERT to service. The operator of a network or service provider provides the user the EXPERT with a confidential key of a registration (PIN code) which has to be entered as into BS, and registrations, assorted prior to the beginning of procedure. Before the tube initiates procedure of the actual registration, she has to know also the BS identifier in which she has to register (for security reasons procedure of a registration can be organized even for system from one BS). Time of carrying out procedure is usually limited, and the key of a registration can be applied only once, it becomes minimizing risk of unauthorized use.
WLL-cistem is important property small time of expansion. It, in particular, is connected with that need for digging of trenches, laying of a cable, and also internal distributing of telephone wires for the building disappears.
In Europe the DECT is the obligatory standard, the frequency range of the DECT in all member countries of the European conference of administrations of mails and telecommunication (CEPT) is reserved only for the systems supporting this standard.
Use of this profile provides two advantages. First, there was a possibility of construction of the mobile DECT networks on the basis of land infrastructure of the GSM networks. Thus costs of creation of infrastructure a set of the DECT significantly decrease as the GSM networks have almost global distribution and constantly increase coverage of territories. In - the second, for operators of the GSM networks there was a possibility of use of dual mobile GSM/DECT terminals for increase in a traffic as the DECT networks support very high density of a traffic. The networks constructed on the basis of the DECT and GSM possess such qualities as high density of a traffic for inactive subscribers in places of the greatest congestion of subscribers at the expense of a subsystem of base stations of the DECT, the big area of a radio covering and high mobility at the expense of a subsystem of base stations of GSM.
The static key is usually used in house communication systems. In this case SCK is unique for each couple ''subscriber/base station'' forming a house communication system. It is recommended to change SCK once in 31 days (the period of repetition of numbers of a shot, differently the risk of disclosure of information significantly increases.