Issued Patents All Time
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4742534 | Telephone receiving equipment for recognizing predetermined combinations of voice-frequency signalling components | Robert J. M. Verbeek, Hendrikus J. Dekker, Johannes H. M. Velthof | 1988-05-03 |