Patent · US Expired

Call transfer method and circuitry

US4560837A · kind A · utility

10Cited by

3References

11Claims

0Family size

Assignee

AT&T Information Systems Inc. · US

Inventors

Robert A. Carson · Indianapolis, US
Francis M. Fenton · Middletown, US
David F. Jones · Holmdel, US

Key dates

Filing date	Aug 15, 1983
Grant date	Dec 24, 1985
Priority date	—
Expiry date	Aug 15, 2003

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S379/914
WIPO fieldTelecommunications
WIPO sectorElectrical engineering

Abstract

In the disclosed call transfer method and circuitry, audibly distinguishable ringing signals at a station set enable an answering party to determine whether a received call is either the original call or a previously answered call. Line status LEDs at each station set give specific visual indications to trace the progress of a call transfer.

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