Detecting whether a telephone line has been disconnected
US5450485A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 19, 1994 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Apr 19, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q3/42
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus for detecting whether a telephone call has been disconnected, which apparatus includes: (a) a click detector for detecting a click and for generating a "click indication"; (b) a telephone handset impact detector for detecting a telephone handset impact and for generating a "handset impact indication"; (c) a silence detector for detecting silence and for storing a "silent indication"; (d) a timer for determining a predetermined time interval and for transmitting a signal to a controller whenever the time period expires; wherein, in response to the signal, the controller analyzes the "click indication", the handset impact indication", and the "silent indication" to determine whether a predetermined sequence of handset impact, clicks, and silence was detected and, if so, for generating a signal indicating that the telephone call has been disconnected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.