| Number | Name | Date | Kind |
|---|---|---|---|
| 4766604 | Axberg | Aug 1988 | |
| 4769834 | Billinger et al. | Sep 1988 | |
| 4791640 | Sand | Dec 1988 |
| Entry |
|---|
| OSSGR, vol. 3, "Feature Specific Documents"; Technical Ref. TSY-000271, FSD 85-01-0100, Calling Card Service-Published by Bell Communications Research-Revision #3, dated Mar., 1988. |
| OSSGR, vol. 3, "Feature Specific Documents"; Technical Ref. TSY-000271, FSD-85-01-0200, Collect Billing-Published by Bell Communications Research-Revision #3, dated Mar. 1988. |