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:
Sep. 03, 1991
Filed:
May. 15, 1990
Randall D Godsey, Carpentersville, IL (US);
Charles T Walneck, Cary, IL (US);
James Santee, Cary, IL (US);
Ronald J Gaulke, Huntley, IL (US);
Luis R Ortez Perez, Rio Piedras, PR (US);
Alexis T Ramos, Carolina, PR (US);
Other;
Abstract
An interface unit for coupling an international-type pay-telephone to a land-based or cellular telephone system. The interfacing unit of the invention has a microcomputer, and an associated EPROM in which is stored the exchanges of the telephone numbers that are accessible by that local payphone-terminal, which EPROM also stores a table indicative of the tariffing rates associated with the respective exchanges called. The invention also includes the tone-detectors for detecting the dialed DTMF digits of the pay-telephone, for the conversion thereof for storage in the microcomputer for the determination of a valid telephone number dialed in order to determine the associated tariffing rates. The tone detectors also detect the tone-signals received from the telephone system. The invention also includes 'isolating' switching circuitry for isolating the coin-operated pay terminal from its couplement to the telephone system until the telephone call has been connected. After a call has been made according to the invention, the microcomputer, after having determined the tariffing schedule for that particular call made, will generate 12K to 16K tone-bursts to the international-type payphone terminal required for debiting the required amount from the coins or credit initially inserted into the payphone.