Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5077744 | Method for error protection in telephone switching installations | Hans-Werner Knefel | 1991-12-31 |
| 4211899 | Circuit arrangement for an indirectly controlled exchange, in particular a telephone exchange | Edmund Ptacnik | 1980-07-08 |