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. 04, 1985
Filed:
Feb. 17, 1984
Peter D Olson, Saratoga, CA (US);
Samuel R Hawes, Jr, Palo Alto, CA (US);
Octel Communications, Inc., San Jose, CA (US);
Abstract
Tone detection apparatus and a corresponding method is disclosed. The improved tone detector and method is for use in a preferred embodiment in a voice message answering system to provide for improved dual tone multi-frequency tone detection where an outgoing analog voice signal is connected to a telephone line. When an incoming call is detected, the tone detector looks at the incoming analog signal and if a dual tone control signal is detected, a filter is switched to filter the outgoing analog signal so that the DTMF tone signal now being detected is filtered out of the outgoing signal. If the incoming signal still detects a tone, the improved tone detector cuts off or disconnects the outgoing signal completely for approximately 20 milliseconds. If a dual tone control signal is still detected, it is determined that it is an incoming control signal and consequently access is required into the voice message system.