IP Library › Granted Patent US 4,273,965
Granted Patent Utility
US 4,273,965 · App. 06/023,999

Tone decoding circuit

Inventors: Michael C. J. Cowpland, Patrick R. Beirne
Patented Case View Patent ↗
Granted: Jun 16, 1981 Filed: Mar 26, 1979
Inventors
Michael C. J. Cowpland
Patrick R. Beirne
Assignee (at issue)
Mitel 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.

Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 4,273,965
App. No.
06/023,999
Filed
1979-03-26
Granted
1981-06-16
Kind
A