Method and apparatus for automatically switching between pulse code and DTMF signals generated by a telephone
US5369697A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1993 |
| Grant date | Nov 29, 1994 |
| Priority date | — |
| Expiry date | Apr 30, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/02
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Dual tone multifrequency (DTMF) signals are automatically generated by a telecommunications device after a telephone number is called. The signals generated to call the telephone number are determined by a manually operated switch indicating pulse code signal generation or dual tone multifrequency signal generation. It is determined that the telephone number has been dialed by detecting a ring-back signal, voice frequency signals, DTMF signals, or data stream signals. Alternatively, if a predetermined period of time, such as ten seconds, passes without the user pressing a number on the keypad, it may be assumed that the telephone number has been dialed. Upon detecting one of these signals or the passage of time, the telecommunications device is controlled to generate only dual tone multifrequency signals for communication with automated services, such as voicemail, telephone banking, reservation systems, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.