Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4882742 | Method for measuring resistances, in particular resistances of subscriber's | Wolfgang Kaiser | 1989-11-21 |
| 4839920 | Method for determining telephone dial pulse parameters independently of subscriber line length | Gabriele Held-Elbert, Wolfgang Kaiser, Wilhelm Koch | 1989-06-13 |