Card-like device having a microprocessor and speaker for communicating with a telephone line
US4995077A · kind A · utility
66Cited by
3References
4Claims
0Family size
Inventor
Key dates
| Filing date | Oct 30, 1989 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Oct 30, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/275
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A card-like device having a microprocessor and a speaker to communicate with telephone line, the device also including a single switch which when depressed by a user first activates the device and then causes a DTMF signal to be generated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.