Patent · US Expired

Key telephone line shunt detector circuit

US4323735A · kind A · utility

1Cited by

7References

13Claims

0Family size

Assignee

Bell Telephone Laboratories, Inc. · US

Inventors

Gerry C. Balzer · Freehold, US
Alan M. Gordon · Del Mar, US

Key dates

Filing date	Sep 26, 1980
Grant date	Apr 6, 1982
Priority date	—
Expiry date	Sep 26, 2000

Classification

Technology area (CPC H)Electricity
CPC primaryH04M9/006
WIPO fieldTelecommunications
WIPO sectorElectrical engineering

Abstract

A line circuit is disclosed for controlling communications over a communication pair between a switching machine and a key telephone station. The line circuit includes a dual sensitivity shunt detector arrangement (103, 104, 105) for improved detection of dc transients and ac ringing voltage signals appearing across the pair. A current diverter circuit (104) switches the sensitivity of the shunt detector arrangement depending on the operating state of the key telephone station.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.