Single wire telephone intercommunication system
US4731821A · kind A · utility
Inventor
Key dates
| Filing date | Nov 13, 1986 |
| Grant date | Mar 15, 1988 |
| Priority date | — |
| Expiry date | Nov 13, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/025
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A residential digital logic circuit telephone system is provided for internal voice communications and digital interfaces control which enables two or more conventional twelve button touch-tone telephone devices to be used as a voice intercommunication system utilizing a single bidirectional conductor and for selectively actuating and controlling the operation of other electrical and electronic devices connected to the system from multiple remote locations. In a preferred embodiment of the system, two to five touch-tone telephones inside a residence may be actuated selectively by means of a ringing signal from any one of said telephones to another or all the other telephones by means of a single conductor bidirectional voice communication circuit arrangement which has been established between a calling telephone and a responding telephone. The intercom ringing system is distinct from the normal ringing signal from an incoming outside call. In another embodiment, a two-way communication resident front door speaker device is connected to the intercommunication system so that visitors may be screened before being admitted to the residence by means of an electronic control signal for u…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.