Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5752229 | Intelligent near-end speech detection | Donald L. Duttweiler, Toshiro Kawahara, Toshio Miki | 1998-05-12 |
| 5668865 | Echo canceler E-side speech detector | Donald L. Duttweiler, Ying Get Tao | 1997-09-16 |