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. 12, 1991
Filed:
Oct. 31, 1988
Lazaro E Alfonso, Miami Lakes, FL (US);
Racal Data Communications Inc., Sunrise, FL (US);
Abstract
A modem side diagnostic loopback apparatus for a two wire communication circuit includes a transformer having a mechanism for connecting to a two wire transmission line on a transmission line side and for coupling to a modem on a modem side. A modem transmitter generates modem transmitter signals and a modem receiver receives signals from the transmission line. A subtracting circuit subtracts the modem transmitter signal from a signal containing both the modem transmitter signal and the received signals. The subtracting circuit may be selectively unbalanced so that the transmitter signals are supplied to the modem receiver and the received signals are inhibited from being received by the modem receiver to effect a loopback.