Granted Patent
Utility
US 5,327,493 · App. 07/694,697
Device for detecting tones on telephone lines
Inventors:
Robert L. Richmond, Martin R. Richmond, Richard Aydelotte, Bennet Blake
Patented Case
View Patent ↗
Granted: Jul 5, 1994
Filed: May 2, 1991
Inventors
Robert L. Richmond
Martin R. Richmond
Richard Aydelotte
Bennet Blake
Assignee (at issue)
Active Voice Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.