Abandoned call control and indication
US5475745A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1991 |
| Grant date | Dec 12, 1995 |
| Priority date | — |
| Expiry date | Sep 4, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for holding a line busy from which a party has disconnected and providing an indication to the other party that the first party has hung up. The invention operates by receiving a call in a telephone switching office from a first subscriber on an incoming line destined for a second subscriber, storing an indication signal signifying that the call has been received; in case the first subscriber has hung up, accessing the indication signal, and as a result sending a signal to the second subscriber which is indicative that the first subscriber has hung up. Such systems are useful in emergency call handling systems, such as 911 emergency call systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.