Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4467143 | Telephone conference amplifiers, and telephone conference bridges incorporating the same | — | 1984-08-21 |
| 4435621 | Speech direction detection circuits for telephone communication devices | — | 1984-03-06 |
| 4320257 | Compensation of transmission losses in a telephone system | — | 1982-03-16 |
| 4232198 | Device for establishing conference calls via at least one telephone exchange switching system | — | 1980-11-04 |