[Asterisk-Users] Traditional Ringback Tone

[Greg Blakely]

I am trying to get Asterisk to emulate the sounds of the earlier
telephone systems, and the settings in [us-old] are pretty helpful.  The
only thing lacking is ringback tone, which is not quite as complex as
the real phone systems of the day.  For example, it is true that a
ringback tone commonly used is 420Hz modulated by 40Hz.  This is what
shows up in [us-old].  But that modulated tone was generally overlaid on
top of real ringing, i.e. 20Hz.  So, using the Asterisk example of
420*40, it would seem that a decent ringback would be (420*40)*20.  But,
of course, that doesn't appear to exist.  If it does, I am missing the
boat on how to do it properly.

So, I have a question:  Is it possible to either (a) do the double
modulation as listed above, or (b) provide recorded wav or gsm sounds as
a background fill while a phone is being rung?  I have recordings of
various types of older central office ringback tones that I'd just love
to be able to put into Asterisk.

I know this sounds a bit arcane.  But Asterisk can do so many things to
order that it really ought to be able to do this, don't you think?

Thanks,

Greg