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Expired
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Laurence Heyworth
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Individual
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Individual
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Publication of GB190905114ApublicationCriticalpatent/GB190905114A/en
H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/02—Constructional features of telephone sets
H04M1/19—Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Mouthpieces or receivers specially adapted therefor
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Engineering & Computer Science
(AREA)
Signal Processing
(AREA)
Telephone Set Structure
(AREA)
Abstract
5114. Heyworth, L. March 2. Mouthpieces.-A sound-proof attachment with an aperture fitting to tLe speaker's mouth is attached to the ordinary mouthpiece. The doublewalled chamber 3 terminates in a pneumatic tube 9 which is attached to the end of the chamber by an elastic band 10. Reference has been directed by the Comptroller to Specification 26,315/08.