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.)
Publication of BE501787ApublicationCriticalpatent/BE501787A/xx
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
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04M—TELEPHONIC COMMUNICATION
H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
H04M11/04—Telephonic communication systems specially adapted for combination with other electrical systems with alarm systems, e.g. fire, police or burglar alarm systems
