Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4887069 | Perimeter intrusion detection system with block ranging capabilities | Walter J. Feller, Edward L. Adams | 1989-12-12 |
| 4879544 | Intrusion detection system | Walter J. Feller | 1989-11-07 |