IP Library › Granted Patent US 4,612,419
Granted Patent Utility
US 4,612,419 · App. 06/688,230

Toll restriction circuit for an electronic telephone station

Inventor: Louis W. Smith
Patented Case View Patent ↗
Granted: Sep 16, 1986 Filed: Jan 2, 1985
Inventor
Louis W. Smith
Assignee (at issue)
GTE Communication Systems 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 4,612,419
App. No.
06/688,230
Filed
1985-01-02
Granted
1986-09-16
Kind
A