Method and apparatus for call source identification
US5070521A · kind A · utility
29Cited by
7References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1991 |
| Grant date | Dec 3, 1991 |
| Priority date | — |
| Expiry date | Jan 11, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W4/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Calls made to a communication unit from the telephone network include a code which can be appended as a predetermined prefix or suffix to the units address code, for alerting the operator that the call was made from the telephone network. Conversely, calls made to the communication unit from another communication unit do not include the code thereby alerting the operator that the call was made from a communication unit. The alert can be accomplished by using visual indicators or and alphanumeric display and/or can be accomplished by use of two distinct audible signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.