Patents by Inventor Allan Y. F. Lee

Allan Y. F. Lee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Telephone line message waiting and ring indicator
    Patent number: 5280523
    Abstract: A visual indicator circuit is provided for visually indicating that a telephone is ringing or that a message is waiting. The circuit includes a visual indicator such as a light emitting diode (LED), a voltage triggering circuit for triggering when a minimum predetermined voltage is applied to the telephone lines, and a current limiting circuit for limiting the current provided to the LED.
    Type: Grant
    Filed: December 19, 1991
    Date of Patent: January 18, 1994
    Assignee: Northern Telecom Limited
    Inventor: Allan Y. F. Lee