Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Autophon AgfiledCriticalAutophon Ag
Publication of CH281290ApublicationCriticalpatent/CH281290A/de
H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/738—Interface circuits for coupling substations to external telephone lines
H04M1/74—Interface circuits for coupling substations to external telephone lines with means for reducing interference; with means for reducing effects due to line faults