(DECT is an acronym that stands for Digital Enhanced Cordless Telephone standard)
DECT was rolled out in 1993, one year after its precursor CT2. This was initiated as early as 1985 by the CEPT (Conférence Européenne des Administrations des Postes et des Télécommunications), while the first digital technologies for wireless telephones were developed both in the UK (CT2) and Sweden (CT3). Prototypes were presented to the CEPT in the fall of 1987, but in January 1988, the CEPT decided on their own concept and handed the task over to the newly founded ETSI (European Telecommunications Standards Institute). At the ETSI, the specifications for DECT were determined by the summer of 1991, and were passed in March 1992 after public consultation. The CEPT reserved the radio band of 1880-1900 MHz for DECT in winter 1989/90.
With the intention of introducing DECT in the end of 1992, the Council of the European Union decided for its member states in June 1991, that the radio band should be secured for DECT by New Year 1991.
In the summer of 1994, the CEPT suggested that over all of Europe, no licence would be required for DECT usage and it became a license free technology. In Germany, the permission for using other wireless telephones was erased by 2009, as the corresponding wave bands were appointed differently. Germany’s Federal Network Agency has prolonged the general assignment for DECT until December 31, 2025.
Globalisation of DECT
As the success of DECT became recognised across the world, other regions of the world adopted DECT but with certain changes to the radio bands requiring a licence.
How DECT Operates
DECT is a connection-oriented technology that is primarily catering to indoor picocell telephony with a reach, i.e. cell radius, of 30 to 50 meters. Outdoors, up to 300 meters of distance can be covered with the maximum rated output power of 250 mW.
The DECT technology uses different frequencies than WLAN and Bluetooth that operate in the open 2.4 GHz radio band, but rather operates in the dedicated 1.8-1.9 GHz radio band which is secure and has active and adequate interference resistance. Speech transmission is executed by using the G.726 codec with a bit rate of 32 kbit/s, producing excellent sound quality of the DECT handsets.
Mobility & Roaming Properties
DECT supports multi-radio base mobility and roaming between different DECT networks with excellent and consistent quality of communications. To switch base stations in a multicell network, the call is forwarded to another cell (auto-handover), while long-term mobility is achieved by connecting to an outside network (auto-roaming). The user can also manually connect to a different base station or another base network. These mobility properties are not completely standardised and require specialised installation based on type of system, base stations, antennas and handsets.
In cases where installers find radio coverage challenging, such as in areas with lots of liquid storage, steel in structured concrete or elevator shafts, directional antennas or repeaters can be used to enhance the radio coverage.