| Number | Name | Date | Kind |
|---|---|---|---|
| 4510351 | Costello et al. | Apr 1985 | |
| 4694483 | Cheung | Sep 1987 | |
| 4763353 | Canale | Aug 1988 | |
| 5179589 | Syu | Jan 1993 | |
| 5299260 | Shaio | Mar 1994 | |
| 5499291 | Kepley | Mar 1996 |
| Entry |
|---|
| ISD/ACD Infoswitch Digital Automatic Call Distributor, Product Specification, Document #610061, pp. 8-27. |
| Aspect Call Center, Product Specification, Release 2-0, Chapters 10, 11 and 13, May 23, 1988. |