Interface circuits for connection to non-dedicated telephone lines
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Mar 29, 1983
Grant Date -
N/A
app pub date -
Mar 25, 1981
filing date -
Mar 25, 1981
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
Receive and transmit paths, for example for frequency shift keyed signals, are coupled to an interface circuit including a line transformer which is permanently connected to the telephone line via a high impedance. The effect of this high impedance on received signals is counteracted by an amplifier and/or a tuned circuit comprising a winding of the transformer. Switches in the interface circuit, responsive to received signals, serve to by-pass the high impedance, and reduce the gain of the amplifier and/or eliminate the effect of the tuned circuit, to permit normal coupling of signals between the telephone line and the receive and transmit paths.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Advertisement
Advertisement
Advertisement
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully