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Off-hook initiated demand assignment communications

  • US 4,220,821 A
  • Filed: 06/16/1978
  • Issued: 09/02/1980
  • Est. Priority Date: 06/16/1978
  • Status: Expired due to Term
First Claim
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1. A method of establishing a communication link between a calling switch and a called switch through originating and terminating relay stations via selected channels from a pool of demand assigned channels between said originating and terminating relay stations, comprising the steps of:

  • (a) generating, on a selected one of a plurality of originating trunks between said calling switch and an originating earth station, first supervisory signals indicative of the on-hook or off-hook state of said trunk, each of said trunks being dedicated to communications destined for a particular called switch via a particular terminating relay station;

    (b) monitoring said selected trunk to detect a first supervisory signal indicative of the off-hook state of said selected trunk;

    (c) determining at said originating relay station the particular called switch and particular terminating relay station to which said selected trunk is dedicated;

    (d) selecting an available channel from said pool of channels to connect said originating and terminating relay stations;

    (e) determining at said terminating relay station the particular called switch to which the selected channel is to be connected; and

    (f) connecting said selected channel to said calling and called switches.

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