Patents Examined by Jacques M. Sanit-Surin
  • Patent number: 5809134
    Abstract: A telephone interface circuit with impedance termination during call pauses, comprising first and second terminals to connect to a telephone line and a line termination branch connected to the first terminal across a decoupling capacitor, and to the second terminal. The line termination branch includes an intersection node, a first switch and a first impedance resistor between the first terminal and the intersection node, and a second switch and a second impedance resistor between the second terminal and the intersection node. The intersection node is connected to ground across a third switch. The first switch, the second switch, and the third switch are controlled by a control unit by first, second and third control lines, respectively. The telephone interface circuit further comprises a ring signal detector that is connected to a microprocessor unit capable of activating the control unit in an interval in which the circuit must be terminated for CLID (Calling Line IDentification) transmission.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: September 15, 1998
    Assignee: STMicroelectronics S.r.l.
    Inventors: Pietro Consiglio, Carlo Antonini