Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4508937 | Method and circuitry for encoding telephone ringing signals | David M. Embree, Martin H. Singer, David R. Vogelpohl | 1985-04-02 |
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4508937 | Method and circuitry for encoding telephone ringing signals | David M. Embree, Martin H. Singer, David R. Vogelpohl | 1985-04-02 |