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Electronic private branch exchange

  • US 4,941,171 A
  • Filed: 12/22/1988
  • Issued: 07/10/1990
  • Est. Priority Date: 01/06/1988
  • Status: Expired due to Term
First Claim
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1. An electronic private branch exchange, comprising:

  • a plurality of line circuits corresponding to a plurality of extension telephone sets respectively;

    a plurality of main wire trunks corresponding to a plurality of main wires respectively;

    incoming signal control means for inputting particular ones of the plurality of extension telephone sets in corresponding relationship to each of the main wire trunks and for causing an incoming signal from that main wire trunk to be responded to at the particular extension telephone sets;

    means for setting from a certain one of the extension telephone sets a time period zone in which an incoming signal tone is to be produced at particular ones of the extension telephone sets; and

    means for sending a signal to the particular extension telephone sets to produce an incoming signal tone at those extension telephone sets in the time period zone set by the setting means, herein the setting means includes;

    a first memory means for storing information indicative of a time period zone in which an incoming signal tone is to be produced at each extension telephone set on reception of an incoming signal from the corresponding main wire trunk;

    a second memory means for storing information indicative of a time period zone in which an incoming signal tone is to be produced;

    means for changing the stored contents of the second memory means from a certain extension telephone set; and

    means for comparing, when there is an incoming signal for the extension telephone sets, the contents of the first memory means and the second memory means and for setting as the extensions telephone set at which the incoming signal tone is to be produced an extension telephone set for which the contents of the first and second memory means are equal.

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