Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6047173 | Call box with keyboard communication | Thomas Leyen, Ronald Sheldrup, Warren Burks | 2000-04-04 |
| 5701338 | Call box with keyboard communication | Thomas Leyen, Ronald Sheldrup, Warren Burks | 1997-12-23 |