Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4864636 | Crystal controlled transmitter | — | 1989-09-05 |
| 4855713 | Learn mode transmitter | — | 1989-08-08 |
| D299422 | Combined annunciator and telephone jack wall plate and a junction box therefor | William W. Williamson | 1989-01-17 |