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Telephone system comprising a satellite

  • US 4,018,993 A
  • Filed: 04/03/1975
  • Issued: 04/19/1977
  • Est. Priority Date: 04/19/1974
  • Status: Expired due to Term
First Claim
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1. Telephone system comprising:

  • a satellite arranged to relay a plurality of one-way signalling channels and one-way speech transmission channels, the latter being paired into two-way speed transmission channels assignable as calling and calling subscriber'"'"'s channels;

    a plurality of earth stations comprising a plurality of line units each of which having a subscriber terminal connected to a subscriber, an input for receiving incoming speech signals, a first output for transmitting signals indicating the on-hook/off-hook condition of the subscriber and a second output for transmitting outgoing speech signals and call signalling data from the subscriber, signalling equipment connected to said first output of said line units for receiving signals indicating the on-hook/off-hook conditions of the subscribers, and including means for transmitting over said signalling channels signal indications about said conditions, and means for receiving over said signalling channels commands about assigned two-way speech transmission channels for calling and called subscribers, and a frequency synthesizer means connected to said input and second output of said line unit and to said signalling equipment for connecting the calling and called subscribers to assigned two-way speech transmission channels under control of said commands in response to signal indications and commands received from said signalling equipment; and

    a central control station comprising central signalling equipment arranged to receive said signal indications and transmit said commands, control equipment connected to said central signalling equipment and arranged to generate said commands assigning two-way speech transmission channels in accordance with the availability of said channels and address said commands to said earth stations, a call signalling data decoding means connected to a data input of said control equipment, and a central frequency synthesizer means connected to said control equipment for connecting said call signalling data decoding means to the speech transmission channels in accordance with the commands being generated by said control equipment.

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