Issued Patents All Time
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6256491 | Voice security between a composite channel telephone communications link and a telephone | Douglas E. Ehlers, Christopher A. Hall | 2001-07-03 |
| 6229897 | Apparatus and method of secured analog voice communication | Max Aaron Caldwell | 2001-05-08 |
| 5838804 | Apparatus and method for providing proper microphone DC bias current and load resistance for a telephone | David L. Dilley | 1998-11-17 |
| 5832076 | Apparatus and method for determining the presence and polarity of direct current bias voltage for microphones in telephone sets | David L. Dilley | 1998-11-03 |
| 5787180 | Method of connecting a scrambler or encryption device to a hand-held portable cellular telephone | Christopher A. Hall, Bradley A. Riensche | 1998-07-28 |