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. 26, 1991
Filed:
May. 12, 1988
Applicant:
Inventors:
Jerry Heep, Weatherford, TX (US);
James Henderson, Fort Worth, TX (US);
Assignee:
Tandy Corporation, Fort Worth, TX (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04J / ; H04M / ;
U.S. Cl.
CPC ...
379160 ; 379159 ; 379163 ; 370 691 ; 370 71 ; 370 30 ;
Abstract
An intercom system for use in combination with a multi-line telephone system wherein the intercom system utilizes the same wire pair for communications between intercom units that is used for normal telephone communications. The intercom system transmits voice signals on two or more frequency modulated channels over a wire pair of a local telephone network. Each intercom unit includes a microprocessor which controls communication activity and protocol in each unit and communicates with other intercom unit miroprocessors via a separate frequency modulated digital signal channel.