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Pat. 11140476 United States, Int. Cl.22 H04R 3/00, G08B 3/10, H02M 1/14, H02M 7/06, H04R 17/00, H04R 29/00. Remote audible alarm accessory for detection instruments with audio outputs : Appl. N 17/182995 : Filed 23.02.2021 : Pub. 05.10.2021 : / Norman Chiu, Paul Goldhagen ; Assignee Us Department of Homeland Security ; NN p. : patents.google.com : URL: https://patents.google.com/patent/US11140476/en?oq=US11140476.html (дата обращения: ДД.ММ.ГГГГ).