×

Voice and data interface circuit

  • US 4,604,741 A
  • Filed: 05/17/1984
  • Issued: 08/05/1986
  • Est. Priority Date: 09/30/1983
  • Status: Expired due to Term
First Claim
Patent Images

1. An interface circuit comprising:

  • (a) means for receiving a first and a second signal having two different frequencies from a line, the line having a first nominal line impedance to the first signal and a second nominal line impedance to the second signal which is less than the first nominal line impedance, said receiving means having an input impedance intermediate said first and second line impedances, and(b) means for applying a representation of the first signal in aiding phase with the first signal and a representation of the second signal in opposing phase to the second signal, to the line whereby the input impedance is raised to at least approximately match the first nominal line impedance with respect to the first signal and lowered to at least approximately match the second nominal line impedance with respect to the second signal.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×