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From: campbell@.ai.mit.edu
Newsgroups: sci.electronics
Subject: phone line power
Message-ID: <13284@life.ai.mit.edu>
Date: 10 Feb 91 05:30:23 GMT
Sender: news@ai.mit.edu
Organization: The Internet
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I am working on a modem circuit and I'd like to power part of it off the
phone line itself. Because of the nature of the phone line, I figured that
the most efficient, reliable +/- 5 volt power supply would be using a
charge pumped device (DC-DC charge pumped devices, there are lots of these
listed at +/-48 volts in the catalogs I have).
1. Will this work? I'm not entirely sure so the only way to tell is to
experiment.
2. Is this really the best method to go about it? Is there some other way?
3. (The part I really wonder about) Will the CPD introduce noise on the
line if I run it in parallel with everything else, so that my original
intention of powering the tone generators/readers by the phone line will
fail due to noise?