Patent · US Expired

Switchable line powered modem

US4578533A · kind A · utility

97Cited by
18References
18Claims
0Family size

Assignee

Inventor

Key dates

Filing dateFeb 17, 1984
Grant dateMar 25, 1986
Priority date
Expiry dateFeb 17, 2004

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH04L12/10
  • WIPO fieldTelecommunications
  • WIPO sectorElectrical engineering

Abstract

A modem for coupling a data terminal or other apparatus to a telephone line and deriving its operating power for both transmitting and receiving operation from the telephone line, and providing electrical isolation between the telephone line and the data terminal. The modem is switchable to provide orginate or answer operation in either of two operating frequency bands.

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