Key telephone exclusion circuit
US4266103A · kind A · utility
4Cited by
8References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1979 |
| Grant date | May 5, 1981 |
| Priority date | — |
| Expiry date | Jul 26, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/002
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An exclusion circuit for use in a key telephone providing an exclusion release feature. Key telephones are excluded or prevented from accessing a busy line by the exclusion circuit. The exclusion release feature, in a key telephone connected to a telephone line, is operated in response to operation of an exclusion release key or partial operation of a hold key, to allow an associated excluded key telephone to connect to a busy telephone line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.