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:
May. 30, 1978
Filed:
Oct. 07, 1976
Shizuo Ando, Kawagoe, JA;
Hiroshi Mizuno, Kawagoe, JA;
Pioneer Electronic Corporation, Tokyo, JA;
Abstract
An automatic telephone answering device includes a diode bridge rectifier having its input terminals connected across a pair of telephone lines through a first switch, and its output terminals connected across a relay coil through a voltage controlled impedance, such as a Zener diode. A relatively high frequency, high voltage call signal is rectified by the bridge and breaks down the diode to energize the relay coil. This closes a relay switch to actuate a control circuit, whose outputs a) actuate a tape recorder unit to play back a prerecorded message to the caller, and b) simultaneously transfer the first switch to connect the tape recorder unit across the telephone lines through a line transformer. The breakdown voltage of the Zener diode is selected to be above the voltage level produced by sound (conversation) signals and busy tone signals, whereby the device presents a high impedance to such signals and is not actuated thereby.