Product manual

System description, DECT air interface
Technical Product Manual - DCT1800-GAP
TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C
© 2006
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Chapter 6 DECT air interface
This chapter introduces the Digital Enhanced Cordless Telecommunications (DECT) standard.
6.1 Introduction
DECT is a standard that defines the air interface between a DECT system and DECT cordless phones.
DECT has been defined by the European Telecommunications Standards Institute (ETSI). DECT is
used for cordless (radio) access to networks, for example the Public Switched Telephone Network
(PSTN). A high speech quality is achieved by using digital transmission. With normal antennas the
range is about 300 m in open space and 30 m inside buildings. With directional antennas and stationary
terminals the range can be up to five kilometres. DECT supports speech as well as data
communications. Furthermore, DECT cordless systems are protected against unauthorised use and
eavesdropping. When compared to cellular systems, DECT offers a high user density (typically 50,000
users per km
2
).
Cellular versus cordless
Cellular systems are country wide networks with standards like NMT, TACS or GSM. The network is
part of the cellular system. The radio range is about 20 km.
Cordless systems provide access to fixed telecommunication networks. The fixed telecommunication
network is not part of the cordless system. Standards for cordless are CT0, CT1, CT2, PHS and DECT.
Cordless systems can be used, for example, at home to get cordless access to the public telephone
line. Or they can be used by companies to get cordless access to their PBX.
Figure 14 shows the difference between cellular systems and cordless systems.
Fig. 14 Cellular and cordless telephone systems
6.1.1 Advantages of DECT
The DECT standard has the following advantages to operators and end users:
• DECT supports uncoordinated system installations, coexisting on a common frequency resource.
• DECT provides a good means for sharing network access between different networks. The same
cordless phones can be equipped with access rights to several public and private networks.
Cellular: NMT , T ACS, GSM Cordless: CT0, CT1, CT2, PHS, DECT
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