The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1984
Filed:
Jun. 21, 1982
Donald W Moses, Minneapolis, MN (US);
Charles Hustig, Hudson, WI (US);
C Ray Ballard, Venice, FL (US);
Applied Spectrum Technologies, Inc., Minneapolis, MN (US);
Abstract
A circuit for coupling digital or analog data signals to a telephone line. A direct coupled transistorized circuit is disclosed having three different impedance conditions: on-hook, off-hook, and loop-test. Consequently, data can be transmitted regardless of the on-hook or off-hook status of the associated telephone sets and regardless of whether or not the telephone sets are in use. In addition, data transmission can range over a frequency spectrum of approximately d-c to frequencies in the data-over-voice range. Because of the variable bridging impedance, the drive impedance is not too low during on-hook ringing and the circuit need not be disconnected during ringing or testing.