Issued Patents 1997
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5640451 | Power cross detection using loop current and voltage | — | 1997-06-17 |
| 5638440 | Protection circuit for telephone systems | Michael A. Nix, Sergio R. Ramirez | 1997-06-10 |
| 5636273 | Integrated ring detection circuit and power cross detection circuit with persistence timers | Sergio R. Ramirez | 1997-06-03 |