Patent classifications
H
ELECTRICITY
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H04
ELECTRIC COMMUNICATION TECHNIQUE
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H04M
TELEPHONIC COMMUNICATION
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Automatic or semi-automatic exchanges
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H04M3/42
Systems providing special services or facilities to subscribers
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H04M3/487
Arrangements for providing information services, e.g. recorded voice services or time announcements
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H04M3/493
Interactive information services, e.g. directory enquiries; ; Arrangements therefor, e.g. interactive voice response [IVR] systems or voice portals
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H04M3/4931
Directory assistance systems
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