Issued Patents 1997
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5640446 | System and method of validating special service calls having different signaling protocols | David Alan Everett, Gary W. Leopold, Lee C. Seydel, Padmanabhan Vijay | 1997-06-17 |
| 5638431 | Calling card validation system and method therefor | David Alan Everett, Gary W. Leopold, Lee C. Seydel, Padmanabhan Vijay | 1997-06-10 |