asterisk users - Mar 2005 - Obscure * command and audio questions

A few bits and pieces that I hope someone here has answers for. 
Basically, I'm in the audio business and I hope to get better control of 
the audio performance in *.

1. I seem to recall seeing a tonelist parameter that allowed tones to be 
set at levels other than 0, for instance !1000/500@-20 would generate 1 
kHz for half a second at -20 dBm0. But this doesn't work and I can't 
find the original reference. Anyone?

2. In ztmonitor there is a bargraph for setting levels, and there's a 
patch available in bug 2783 to show numeric values for the levels on tx 
and rx paths. Has anyone calibrated these numbers to dBfs or dBm0? They 
look like a straight decimal conversion of the audio bitstream but how 
literal is this?

3. Levels from app_milliwatt and Playtones are different. app_milliwatt 
says it's generating a mu-law bitstream but I can't find the code
that's
actually doing this. What does Playtones use?

4. Is it possible to tweak the gains of the transcoding modules without 
patching the source? What about non-transcoded calls like straight a-law 
to a-law connections, for instance?

5. In various docs rxgain and txgain in zapata.conf are said to be in dB 
or percent or some arbitrary number. My C is very rusty, but in 
chan_zap.c the number seems to be converted to a linear gain number 
using a formula for voltage gain rather than power gain.  Has anyone 
calibrated this?

Thanks

David Josephson