Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4602132 | Key telephone system | Rikio Sato | 1986-07-22 |
| 4595800 | Key telephone system | Rikio Sato | 1986-06-17 |
| 4520235 | Electronic key telephone system | Kenichi Morikawa, Mitsuo Katanuma | 1985-05-28 |