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 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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