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:
Jun. 01, 1976
Filed:
Dec. 19, 1974
Raymond Ma, Seattle, WA (US);
Tel-Tone Corporation, Kirkland, WA (US);
Abstract
A circuit for preventing the automatic operation of the time-out portion of a tone-to-pulse converter until after the first DTMF digit is dialed is disclosed. When a calling party goes OFF HOOK, the forward loop current flowing in the tip and ring in leads is sensed. The sensed current creates a binary zero signal that sets a latch circuit. The latch circuit inhibits the automatic operation of the time-out portion of the tone-to-pulse converter until the latch circuit is reset. The latch circuit is normally reset by the first output of the tone-to-pulse converter adapted to create a rotary dial-type pulse. Alternatively, going ON HOOK without creating a DTMF digit resets the latch circuit, as does the occurrence of a rotary dial pulse on the tip and ring in leads.