DECT Basics

DECT (Digital Enhanced Cordless Telecommunications) is a flexible digital radio access standard for cordless communications in residential, corporate and public environments. DECT provides for voice and multimedia traffic, and contains many forward-looking technical features that allow DECT-based cordless systems to play a central role in important new communications developments such as Internet access and interworking with other fixed and wireless services such as ISDN and GSM.

The DECT standard makes use of several advanced digital radio techniques to achieve efficient use of the radio spectrum; it delivers high speech quality and security with low risk of radio interference and low power technology.

TDMA (Time Division Multiple Access) radio access, with its low radio interference characteristics, provides high system capacity to handle up to 100'000 users per km² floor space in an office environment.

ADPCM (Adaptive Differential Pulse Code Modulation) speech encoding ensures a DECT cordless phone very high speech quality, comparable to wireline telephony.

DCS/DCA (Dynamic Channel Selection / Allocation) is a unique DECT capability that guarantees the best radio channels available to be used. This happens when a cordless phone is in stand-by mode, and throughout a call. This capability ensures that DECT can coexist with other DECT applications and with other systems in the same frequency, with high-quality, robust and secure communications for end-users.

Other features of the DECT standard include encryption for maximum call security and optimized radio transmission for maximum battery life.

DECT basic technology and the various profiles enhance the DECT standard, introducing evolutionary applications and services. The GAP profile, for example, ensures interoperability of equipment from different providers for voice applications.

VoIP resounds throughout the land. The extension of wireless local data networks and digital voice control over the internet protocol (IP) offers completely new applications, far in excess of what was previously available to users. DECT is the ideal technology for the wide range of IP telephony applications. DECT telephones offer brilliant voice quality also in IP infrastructures via broadband connections. DECT as an established and reliable standard supports the cutting-edge mobile IP telephony with HiFi voice quality - with secure, stable and cost-saving features.

Top of the range DECT cordless phones guarantee the highest technical solution for business sites. The voice encoding of DECT assures tap-proof security of voice and data communication.

Background Information

How cordless services have been deployed between 1989 and 1993

Overview of Technical Parameters

DECT is also an ITU IMT-2000 [REF ITU RM 145729] family member, called IMT-FT, the only member that provides for uncoordinated installations on an unlicensed spectrum.

DECT has for many years already spectrum allocated within the IMT-2000 bands available in more than 110 countries (information from DECT Forum).

DECT carriers are specified in EN 300 175-2 annex F for the whole frequency range 1.880 GHz to 1.980 GHz and 2.010 GHz to 2.025 GHz.

The most common protected spectrum allocation is 1.880 GHz to 1.900 GHz, but outside Europe spectrum is also available in 1.900 GHz to 1.920 GHz and in 1.910 GHz to 1.930 GHz (Latin America).

Switching the physical channel while maintaning the communication link is a feature of both cordless and mobile systems. The Dynamic Channel Selection (DSC) algorithm of the DECT system is used in the radio interface between the portable parts and the fixed part The main feature this algorithm is that the Portable Parts select the radio channels and time slots for the call. In GSM, another mobile radio system, the basestations control the allocation of these resources although assisted by the mobiles. We specify the DECT algorithm as a refinement of the GSM system.

Licensing

The use of radio equipment is generally subject to licensing under Section 1 of the Wireless Telegraphy Act 1949 (WT Act). However, Exemption Regulations have been made which means that users of cordless telephones for domestic or private use, which have been type approved to the relevant specification, do not need a separate WT Act licence.

Type Approval

Approved cordless telephones are those models which manufacturers have had type approved to the appropriate specification. Type approval testing is carried out by accredited and authorised Test Houses. The names and addresses of such Test Houses are listed in the Information Sheet RA 293 titled A List Of Accredited Test Houses Acceptable to the Radiocommunications Agency for Type Approval and EMC Type Examination of Radio Equipment. Information Sheets are obtainable from the RA Library, the address of which is given at the end of this notice.