Issued Patents 1997
Showing 1–6 of 6 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5673310 | Hierarchical switch support of services for subscribers of separate centrex exchanges | Donald Lee Andruska | 1997-09-30 |
| 5673311 | Hierarchical switch support of services for subscribers directly served by local exchange carriers | Donald Lee Andruska | 1997-09-30 |
| 5673312 | Control of call features provided to a subscriber by a hierarchical telecommunication switch | Donald Lee Andruska | 1997-09-30 |
| 5668860 | Call screening at a hierarchical switch based on organizational membership of the parties | Donald Lee Andruska | 1997-09-16 |
| 5652790 | Hierarchical switch support of services for subscribers based on organizational membership | Donald Lee Andruska | 1997-07-29 |
| 5646985 | Hierarchical switch support of services for subscribers of independent private branch exchanges | Donald Lee Andruska | 1997-07-08 |