FR759288A - Dispositif destiné à être connecté à des appareils d'installations téléphoniques pour produire un effet acoustique amplifié
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Dispositif destiné à être connecté à des appareils d'installations téléphoniques pour produire un effet acoustique amplifié
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H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
H04M1/6033—Substation equipment, e.g. for use by subscribers including speech amplifiers for providing handsfree use or a loudspeaker mode in telephone sets
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Signal Processing
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FR759288D1932-08-051933-08-04Dispositif destiné à être connecté à des appareils d'installations téléphoniques pour produire un effet acoustique amplifié
ExpiredFR759288A
(fr)