Document Type and Number:
Japanese Patent JPS4329908
Kind Code:
B1
Abstract:
1,019,410. Automatic exchange systems, WESTERN ELECTRIC CO. Inc. Dec. 16, 1964 [Dec. 16, 1963], No. 51132/64. Heading H4K. In a system in which VF current is sent over a channel in the idle condition from a source 17 and is cut off when the channel is taken into use, the transmitting terminal includes a filter 20 which substantially attenuates the signalling frequency occurring in speech or arising from external sources which might otherwise produce a false idle indication at the receiving end. A 4-wire junction is shown, and the receive channel feeds a tuned signal receiver 48 and a speech amplifier 44 which preferably includes a filter 50 in the negative feedback path to emphasize the response at the signalling frequency and thus compensate for the attenuation introduced at the transmitter.
Application Number:
JP7051564A
Publication Date:
December 21, 1968
Filing Date:
December 16, 1964
Export Citation:
International Classes:
H04Q1/446