Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4538028 | Apparatus for use with key telephone system with wireless telephone device | Frank Keller | 1985-08-27 |
| 4538029 | Apparatus for use with key telephone system with wireless telephone device | Frank Keller | 1985-08-27 |