Issued Patents 1989
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4873682 | Digital key telephone system | George F. Irwin, Paul J. Smelters, Ronald J. Maginley | 1989-10-10 |
DR
David Joseph Robertson
Overall (1989): #121,906 of 140,708Top 90%
1
Patents 1989