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Special Information Tones
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lau...@vortex.uucp
Oct 15, 1985, 1:37:06 PM10/15/85
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The set of three tones you hear on many recordings these days are
called "Special Information Tones." They vary for different sorts
of situations (e.g. unassigned number, all circuits busy, etc.)
They use a variety of rather oddball tone frequencies that were
detailed in an issue of BSTJ some years back.
called "Special Information Tones." They vary for different sorts
of situations (e.g. unassigned number, all circuits busy, etc.)
They use a variety of rather oddball tone frequencies that were
detailed in an issue of BSTJ some years back.
These tones can be used by automated line/trunk testing equipment to
determine the termination status of calls.
--Lauren--
lau...@vortex.uucp
Oct 17, 1985, 3:42:19 AM10/17/85
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I hate to contradict someone at an AT&T site, but the SIT's are
NOT MF (blue box) tones. They are a bunch of odd frequencies
that are unrelated to both MF and DTMF (touch tone). I remember
noticing that they were a set of really "strange" frequencies
when I read the original BSTJ article regarding them.
NOT MF (blue box) tones. They are a bunch of odd frequencies
that are unrelated to both MF and DTMF (touch tone). I remember
noticing that they were a set of really "strange" frequencies
when I read the original BSTJ article regarding them.
--Lauren--
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