Dial pulse key telephone intercom system
US4086444A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1976 |
| Grant date | Apr 25, 1978 |
| Priority date | — |
| Expiry date | Nov 4, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/002
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The system receives subscriber station address information in the form of dial pulses transmitted from a calling station along a common intercom circuit and selectively accesses a called subscriber station having a corresponding station address in order to produce a call indication ring-out thereat. The system includes a hook condition detector circuit which controls multiple system functions with respect to the on-hook and off-hook status of the calling station, and further includes a dial pulse detector circuit which effects additional control with respect to completion of dialing by the calling station. The system is suitable for use with ten or varying numbers of subscriber stations and may include, for applications having more than ten subscriber stations, appropriate transfer and associated output control circuitry for double digit operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.