TREA

Interconnection arrangements not involving centralised switching

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Industry

  • CPC
  • H04M9/00
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Parent Industries

HELECTRICITY H04Electric communication H04MTELEPHONIC COMMUNICATION

Current Industry

H04M9/00Interconnection arrangements not involving centralised switching

Sub Industries

H04M9/001Two-way communication systems between a limited number of parties H04M9/002with subscriber controlled access to a line H04M9/003Transmission of control signals from or to the key telephone set; signalling equipment at key telephone set H04M9/005with subscriber controlled access to an exchange line H04M9/006Exchange line circuits H04M9/007wherein the key telephone sets are star-connected to a central unit by a limited number of lines H04M9/008Multiplex systems H04M9/02involving a common line for all parties H04M9/022Multiplex systems H04M9/025Time division multiplex systems H04M9/027Frequency division multiplex systems H04M9/04involving a separate line for each pair of parties H04M9/06involving combinations of interconnecting lines H04M9/08Two-way loud-speaking telephone systems with means for suppressing echoes or otherwise conditioning for one or other direction of traffic H04M9/082using echo cancellers H04M9/085using digital techniques H04M9/087using different frequency bands for transmitting and receiving paths ; using phase shifting arrangements H04M9/10with switching of direction of transmission by voice frequency
Industries