Ring detector circuit for centrally located answering and recording equipment
作者： Dean Wilson Danner
DOI:
关键词: Electrical engineering 、 Single line 、 Detector 、 Optical isolator 、 Recording system 、 Ringing 、 Comparator 、 Ring (mathematics) 、 Telephone equipment 、 Engineering
摘要: A telephone answering and recording system designed for installation in a centralized location remote from the customer's premises. single line is employed normal operation between equipment centrally located equipment. Facilities are also included which permit customer to access telephones other than his own regular instrument. The includes ringing signal detection means comprising an optical isolator, comparator, counting means.
lens.org 参考文章(7)
Edward A. Marheine, Intercept arrangement for key telephone systems ,(1974)
E Mason, Automatic telephone answering device for use with a data modem ,(1972)
Zarouni Alfred, Telephone answering equipment ,(1962)
Hoven E, Owen J, Frequency-selective ringing current sensor for telephone line ,(1972)
Richard A. Morstadt, Thomas J. Kopec, Common audible signaling circuit ,(1973)
James R Darwood, Voice operated electric circuit ,(1973)
James R. Darwood, Telephone answering system with ring detector ,(1975)