| Number | Name | Date | Kind |
|---|---|---|---|
| 4446336 | Bethel et al. | May 1984 | |
| 4766604 | Axberg | Aug 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-00271 FSD-85-01-0200, Collect Billing--Published by Bell Communications Research--Revision #3 dated Mar. 1988. |