Listening device for tracing line continuity and detecting telephone dial tone
US5887051A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1997 |
| Grant date | Mar 23, 1999 |
| Priority date | — |
| Expiry date | Jul 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A pocket-size hand-held testing tool is provided for testing the operation of telephone lines and tracing the location of electric wires, including a sound signal channel with an output speaker, a dial tone detection circuit for detecting a dial tone on a telephone line, a probe for capacitively receiving a signal from a particular wire in a bundled wire cable to identify that wire as one to which a tracing signal is being applied at the other end of the cable, and a momentary switch normally connecting the dial tone detection circuit into communication with the sound signal channel but manually depressable to instead selectively switch the probe into communication with the sound signal channel while disconnecting the dial tone detection circuit from it.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.