Extension-in-use exclusion apparatus
US6061438A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1994 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Jun 20, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/715
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An extension-in-use exclusion apparatus is for use in a telephone system. The system has a telephone device, a telephone line, and two telephone extensions connected to the line. The apparatus is connected between one extension and the telephone device. The apparatus has an exclusion controller connecting the line to the telephone device when all extensions other than the extension for the telephone device are on-hook and the telephone device extension is off-hook. The exclusion controller does not connect the line to the telephone device when another extension is off-hook and the telephone device is off-hook. A user operable switch can instruct the exclusion controller to connect the line to the telephone device when another extension is off-hook and the telephone device is off-hook. The apparatus automatically returns to exclusion mode when the telephone device returns to off-hook. A by-pass allows FSK signals to pass directly through to the telephone device. The apparatus has no polarity and is symmetrical.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.