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 BE416075ApublicationCriticalpatent/BE416075A/xx
H04Q1/00—Details of selecting apparatus or arrangements
H04Q1/18—Electrical details
H04Q1/30—Signalling arrangements; Manipulation of signalling currents
H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
H04Q1/45—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling
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Engineering & Computer Science
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Computer Networks & Wireless Communication
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Radar Systems Or Details Thereof
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Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents
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