[fa.telecom] Daa Daa Daa... The number you have dialed...

mgrant@GYMBLE.UMD.EDU (Michael A. Grant) (10/15/85)

I once asked my bussiness office about those tones when I first started
hearing them.  I was told that there was quite a few different 3 tone
sequences, all going from low to high.  Something which hears those tones
is suposed to be able to distinguish what kind of error you got making
your call.  I've yet to see any modem de-cypher them though.  And what
I can't figure out is why there so &^%$#@! loud.
-MGrant