发明名称 INTRINSICALLY SAFE TELEPHONE
摘要 An intrinsically safe telephone as provided for use in hazardous areas. The telephone includes a single line instrument located in the hazardous area which, in turn, is coupled by a two-wire transmission path to a shunt diode barrier and a telephone line interface located in a safe environment. The telephone line interface reduces power of incoming ringing and audio signals. The telephone line interface further includes an off-hook indicating circuit which senses when the single line instrument is off-hook. The intrinsically safe telephone is useful in all hazardous environments as classified by the National Electrical Code and requires no explosion-proof housing.
申请公布号 CA2036521(A1) 申请公布日期 1992.01.14
申请号 CA19912036521 申请日期 1991.02.18
申请人 GAI-TRONICS CORPORATION 发明人 BRENEMAN, BRIAN H.;DALE, BRUCE
分类号 H04M1/18;H04M1/60;H04M1/78;H04M9/00;H04M19/04;H04M19/08 主分类号 H04M1/18
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