Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4856056 | Apparatus for timely controlling the sound characteristic of a signaling means of a voice communication device | — | 1989-08-08 |
| 4802208 | Hot-line device for telephone sets | — | 1989-01-31 |
| 4794640 | Switching control apparatus for intercom-telephone sets | — | 1988-12-27 |
| 4644106 | Apparatus for timely controlling the sound characteristic of a signaling means of a voice communication device | — | 1987-02-17 |