Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request
From: martin@cod.nosc.mil (Douglas W. Martin)
Newsgroups: comp.dcom.telecom
Subject: How Were Telephone Sounds Chosen?
Message-ID: <1977@accuvax.nwu.edu>
Date: 8 Dec 89 23:37:34 GMT
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     I posted this request several months ago, but got no response.
Anyone with any ideas or speculations is greatly appreciated.

     I am interested in finding literature references on how the
various telephone sounds, e.g. dial tone, busy signal, and the
decaying tone associated with credit card calls, were chosen.  What
kinds of psychoacoustic research were done to determine that these
sounds are easily remembered, easily discriminated in noise, or less
annoying than other sounds which could have been selected.  I am
looking for references on how these sounds were selected.

     Also, can anyone supply information about the frequency,
duration, etc. for the off-hook alarm signal?

Thanks,
Doug Martin
martin@nosc.mil