Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4862492 | Measurement of transmission quality of a telephone channel | — | 1989-08-29 |
| 4852149 | Automated call filter | Charles R. Walden Jr., Louis Francz, Jay L. Gerbehy | 1989-07-25 |