Patent classifications
H
ELECTRICITY
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H04
ELECTRIC COMMUNICATION TECHNIQUE
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H04M
TELEPHONIC COMMUNICATION
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3/00
Automatic or semi-automatic exchanges
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H04M3/42
Systems providing special services or facilities to subscribers
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H04M3/428
Arrangements for placing incoming calls on hold
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H04M3/4285
Notifying, informing or entertaining a held party while on hold, e.g. Music On Hold
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