Patent · US Expired

Detection of a call-waiting tone by a modem

US6333974A · kind A · utility

9Cited by
8References
40Claims
0Family size

Assignee

Inventors

Key dates

Filing dateMay 26, 1998
Grant dateDec 25, 2001
Priority date
Expiry dateMay 26, 2018

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH04M3/4281
  • WIPO fieldTelecommunications
  • WIPO sectorElectrical engineering

Abstract

Reliable detection of a call-waiting tone is provided by employing a correlation based technique. A modem or other device employing such a technique need not rely on carrier drop detection and is generally insensitive to other energy or noise on the line.

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