Key telephone area voice paging circuit and method
US4440989A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1982 |
| Grant date | Apr 3, 1984 |
| Priority date | — |
| Expiry date | Mar 22, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/002
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An area voice paging feature is provided in a key telephone system wherein key telephone station sets each have a loudspeaker circuit responsive to a d.c. control signal, on an associated signalling path, to audibly reproduce voice band signals superimposed on the d.c. control signal. A page control interface circuit generates a page control signal in response to receiving the d.c. control signal, when the d.c. control signal is directed to the interface circuit on one of the signalling paths, and generates a d.c. biased voltage signal having an a.c. component corresponding to the voice band signals. Page switches each have an output connected in common with a predetermined respective one of the signalling paths and are each responsive to the page control signal to couple the d.c. biased voltage signal to the respective signalling path. Each loudspeaker circuit, in a group as selected by the page switches, receives the d.c. biased voltage signal and produces and audible signal corresponding to the a.c. component. In the case where one of the signalling paths is already in use, this is indicated by the presence of the d.c. control signal on the signalling path. In this event, a logi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.