Article View: sci.electronics
Article #21114Sensing telephone off-hook
From: Jonathan Dubman
Date: Tue, 11 Apr 1989 04:44
Date: Tue, 11 Apr 1989 04:44
16 lines
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1154 bytes
I realize this was asked recently, but I just started reading this newsgroup and I think I missed some of the responses. We need a sensor circuit to determine whether a telephone line is off-hook. I have lots of parts handy and I suspect it is a relatively simple voltage-range detector circuit, but I'm not sure of the voltages. Is it this simple? The reason we need this sensor is to prevent somebody from interrupting a download in progress. It would be more fun and slightly cheaper to build rather than buy if the circuit is indeed simple. Thank you very much! -Jonathan Dubman 128a-3db@web.berkeley.edu
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arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!e260-3b.berkeley.edu!128a-3dbShow Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!e260-3b.berkeley.edu!128a-3db From: 128a-3db@e260-3b.berkeley.edu (Jonathan Dubman) Newsgroups: sci.electronics Subject: Sensing telephone off-hook Keywords: sensor telephone off-hook Message-ID: <22901@agate.BERKELEY.EDU> Date: 11 Apr 89 04:44:14 GMT Sender: usenet@agate.BERKELEY.EDU Reply-To: 128a-3db@e260-3b.berkeley.edu (Jonathan Dubman) Distribution: usa Organization: University of California, Berkeley Lines: 16