Issued Patents 1997
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5699421 | Telephone answering device with low cost dual tone multi-frequency detector | Alex Nirshberg, Frank Sacca | 1997-12-16 |
| 5606598 | Telephone answering device with direct telephone line interface | Stephen B. Knuth | 1997-02-25 |