Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6490348 | Switching system for providing an improved call waiting service | Masahiko Yamagishi | 2002-12-03 |
| 6192120 | Method and apparatus for controlling call waiting service | Masahiko Yamagishi | 2001-02-20 |