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. 26, 1978
Filed:
Apr. 29, 1977
Shizuo Ando, Kawagoe, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A start circuit for a telephone answering device for distinguishing between a standard 16 Hz bell signal with a repeating one second on -- two second off pattern, and extraneous dial signals having ten pulses or less. The number of sequential input pulses are accumulated in a first binary counter BC.sub.1 whose '4' and '8' stages are coupled to a NAND gate G.sub.4, and the number of successive input bursts each containing at least 12 pulses are accumulated in a second binary counter BC.sub.2 in response to the NAND gate output. A final, bell signal recognition output is produced when the second counter registers a predetermined count. The first counter is reset approximately 0.3 second after the termination of a first input burst in preparation for a possible second burst, while the second counter holds its count for approximately 5 seconds. The NAND gate output also disables the first counter after a count of 12 is reached.