DECT

From HFUnderground

Jump to: navigation, search

Digital enhanced cordless telecommunications (Digital European cordless telecommunications)


Originally designed as a cordless telephone standard to replace the half dozen different analog and digital cordless telephone technologies operating on various frequency bands from 1.6-1.7 MHz to 30-50 MHz (30 MHz and 31 MHz band paired with the and 39 MHz and 40 MHz band, 1.610-1.8 MHz paired with 47 MHz VHF) in the UK, 43-50 MHz in the US) and other VHF/UHF/SHF bands such as 800 MHz band, 890 MHz band, 900 MHz band (902-928 MHz), the 2.4 GHz band 5 GHz band and 5.8 GHz bands among many others.

Usually known by the acronym DECT, or, in the United States, DECT 6.0, is a standard primarily used for creating cordless telephone systems. It originated in Europe and is now used worldwide (with frequency allocations differing from country to country...however, there are significant efforts at standardization as with LPD or Part 15 devices in the EU (CEPT), etc.

DECT based systems may be used for full duplex intercom systems, on-site VoIP PBX type systems ePBX systems, multi-site cordless phone with handset to handset communications capability, paging, etc. There are similar multi-site long range business cordless phone systems (VoIP based, traditional PBX hardline based) on the market, including systems on the 900 MHz band that offer significant range improvement (using multiple base stations and high gain antennas, creating a private cellular telephone network for a large office building complex, retail store, warehouse or other facilities. Many of these systems blur the line between two-way radio, cordless telephone systems, intercoms and traditional business phone systems.

Background

DECT Theory & Details Communication Typical Frequency Range is 1700-1940 MHz or 1.7 GHz to 1.94 GHz, usually simply referred to as 1.9 GHz band. General: Digital enhanced cordless telecommunications Modulation: TDMA, GMSK, GFSK Combination method. DECT uses MC (multi carrier): 10 RF channels; channel 10 at 1881.792 MHz; other channel numbers in decreasing order at 1.782 MHz intervals. DECT uses TDMA (time division multiple access) within a channel: 24 timeslots spaced 10 ms apart; 1 – 12 downlink, 13 – 24 uplink. DECT devices automatically look for the carrier that gives the best transmission quality (dynamic channel selection / allocation). DECT uses TDD (time division duplex) In full duplex mode for telephony in 2 channels always separated by 5 ms and also on different frequencies.

Frequencies

DECT bands DECT frequency bands DECT channels

Full coverage usually considered roughly the 1.7 GHz to 1.9 GHz bands, but this varies significantly from country to country.

1770 MHz to 1939 MHz with obvious gaps depending on country allocation. Usually the 1.9 GHz band. This frequency space is valuable and in many areas may be allocated to other services such as 4G mobile cellular, 4G LTE mobile systems or 5G cellular systems.

Channel spacing is usually 1.728 MHz, with some exceptions and offsets. Power limits, duty cycle limitations and ERP/EIRP limits also vary considerably from country to country.

  • 1920 MHz - 1930 MHz - United States and Canada - DECT 6.0 - Unlicensed Personal Communications Service or UPCS, Part 15 Subpart D (15.301 through 15.323)
  • 1910 MHz - 1930 MHz - Latin America (excluding Brazil)
  • 1910 MHz - 1920 MHz - Brazil
  • 1893 MHz - 1906 MHz - Japan - J-DECT specification
  • 1786 MHz - 1792 MHz - South Korea
  • 1880 MHz - 1900 MHz - Europe, most of Asia and numerous other countries - DECT-2020


DECT channel plan - ETSI standardization document - not all channels are authorized in all areas.

  • Carrier ID 9 / Channel 9 - 1881.792 MHz
  • Carrier ID 8 / Channel 8 - 1883.592 MHz
  • Carrier ID 7 / Channel 7 - 1885.248 MHz
  • Carrier ID 6 / Channel 6 - 1886.876 MHz
  • Carrier ID 5 / Channel 5 - 1888.704 MHz
  • Carrier ID 4 / Channel 4 - 1890.432 MHz
  • Carrier ID 3 / Channel 3 - 1892.160 MHz
  • Carrier ID 2 / Channel 2 - 1893.888 MHz
  • Carrier ID 1 / Channel 1 - 1895.616 MHz
  • Carrier ID 0 / Channel 0 - 1897.344 MHz
  • Carrier ID 10 / Channel 10 - 1899.072 MHz
  • Carrier ID 11 / Channel 11 - 1900.800 MHz
  • Carrier ID 12 / Channel 12 - 1902.528 MHz
  • Carrier ID 13 / Channel 13 - 1904.256 MHz
  • Carrier ID 14 / Channel 14 - 1905.984 MHz
  • Carrier ID 15 / Channel 15 - 1907.712 MHz
  • Carrier ID 16 / Channel 16 - 1909.440 MHz
  • Carrier ID 17 / Channel 17 - 1911.168 MHz
  • Carrier ID 18 / Channel 18 - 1912.896 MHz
  • Carrier ID 19 / Channel 19 - 1914.624 MHz
  • Carrier ID 20 / Channel 20 - 1916.352 MHz
  • Carrier ID 21 / Channel 21 - 1918.080 MHz
  • Carrier ID 22 / Channel 22 - 1919.808 MHz
  • Carrier ID 23 / Channel 23 - 1921.536 MHz
  • Carrier ID 24 / Channel 24 - 1923.264 MHz
  • Carrier ID 25 / Channel 25 - 1924.992 MHz
  • Carrier ID 26 / Channel 26 - 1926.720 MHz
  • Carrier ID 27 / Channel 27 - 1928.448 MHz
  • Carrier ID 28 / Channel 28 - 1930.176 MHz
  • Carrier ID 29 / Channel 29 - 1931.904 MHz
  • Carrier ID 30 / Channel 30 - 1933.632 MHz
  • Carrier ID 31 / Channel 31 - 1935.360 MHz
  • Carrier ID 32 / Channel 32 - 1937.088 MHz



This site is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. Some links may be affiliate links. We may get paid if you buy something or take an action after clicking one of these.