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Power feed for Ethernet telephones via Ethernet link

  • US 6,115,468 A
  • Filed: 03/26/1998
  • Issued: 09/05/2000
  • Est. Priority Date: 03/26/1998
  • Status: Expired due to Term
First Claim
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1. A power feed system for Ethernet telephones, said system comprising:

  • a first transformer including a first primary, a second primary, a first secondary with a first center-tap and a second secondary with a second center-tap, said first primary for coupling to a first pair of conductors, said second primary for coupling to a second pair of conductors;

    a second transformer including a first primary with a first center-tap, a second primary with a second center-tap, a first secondary and a second secondary, said first and second secondaries for coupling to an Ethernet telephone;

    an Ethernet link including a third pair of conductors is and a fourth pair of conductors, said third pair of conductors connecting said first secondary of said first transformer with said first primary of said second transformer and said fourth pair of conductors connecting said second secondary of said first transformer with said second primary of said second transformer;

    a direct current power supply having a first output potential on a first line and a second output potential different from said first output potential on a second line, said first line connected to said first center-tap of said first transformer and said second line connected to said second center-tap of said first transformer;

    a first potential input of an Ethernet telephone coupled to said first center-tap of said second transformer; and

    a second potential input of an Ethernet telephone coupled to said second center-tap of said second transformer.

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