Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4555597 | Transient resistant key operated pulse generating calling device circuit | Eduard F. B. Boeckmann | 1985-11-26 |
| 4447674 | Electronic hold release circuit | Gary Grantland, Hugh S. Montgomery, Eduard F. B. Boeckmann | 1984-05-08 |
| 4440981 | Electronic hold circuit | Gary Grantland, Hugh S. Montgomery, Eduard F. B. Boeckmann | 1984-04-03 |
| 4309573 | Loudspeaking substation circuit | Gary Grantland | 1982-01-05 |