Telephone system
US4706275A · kind A · utility
458Cited by
5References
23Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1985 |
| Grant date | Nov 10, 1987 |
| Priority date | — |
| Expiry date | Nov 13, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M17/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A telephone system enabling prepayment for telephone calls, wherein special code and credit information is stored in memory in special exchanges and debited as the call progresses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.