Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4821316 | Key telephone system | Yasuo Kobayashi, Ryuzo Sugiura, Masatoshi Ikeda | 1989-04-11 |
| 4794641 | Data transmission system of key telephone system | Kenichi Kanno, Hisami Ojima | 1988-12-27 |
| 4759055 | Key telephone system | Katsuyuki Sekine, Ryuzo Sugiura | 1988-07-19 |
| 4731820 | Data transmission system of key telephone system | Kenichi Kanno, Hisami Ojima | 1988-03-15 |