Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5852785 | Secure access telephone extension system and method in a cordless telephone system | David Bartholomew, Alma K. Schurig | 1998-12-22 |
| 5530737 | Secure access telephone extension system and method | David Bartholomew, Alma K. Schurig | 1996-06-25 |
| 5319634 | Multiple access telephone extension systems and methods | David Bartholomew, Alma K. Schurig | 1994-06-07 |