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From: Leichter-Jerry@CS.YALE.EDU@venus.ycc.yale.edu
Newsgroups: comp.dcom.telecom
Subject: Re: More on Remote Eavesdropping with an Unmodified Telephone Set
Message-ID: <6195@accuvax.nwu.edu>
Date: 9 Apr 90 13:34:53 GMT
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X-Telecom-Digest: Volume 10, Issue 242, Message 4 of 9


Larry Lippman's recent comments - for which this reader says "much
thanks" - bring to mind a an old story.  It may be "urban legend", or
there may be something behind it.

It's claimed that the reason Ma Bell was so slow to replace the little
incandescent bulbs in multi-line phones with LED's was a security
problem.  It seems that voices on the line modulate the power
available to the indicators.  The reluctance of the old incandescents
was high enough that no useful information could be gotten from
them, but it was alleged that the LED's provided a nice clear signal
which could be read, say, with a decent telescope and a little
equipment, from the building across the street.

			-- Jerry