asterisk users - Jul 2007 - analog call progress - simplified ( I hope)

Asterisk gurus,

To have analog call progress (which as far as I know asterisk does not 
have right now)
does it not come down to 4 states to detect - and I hope that some 
asterisk gurus can
implement those 4 states easily.

I see this as 4 states:
Busy - a 50% duty  cycle
Ringing - a % on duty and MORE of a bigger % off duty cycle - or 
basically not BUSY and not TALK detect
Talk - something that is not at a 50% duty cycle and periodic in nature.
no data yet - state before ring or busy.

These 4 states seem like they should not be that difficult to detect (I 
hope).

I dont think we "care" about what tone is present or anything like
that.
Its simply trying to determine
4 states in the least amount of CPU needed.

I have been hoping for a long time to have something similar to the old 
dialogic call progress for analog cards
in asterisk. Havent seen it though.

I have played with the zapata.conf callprogress and it says HIGHLY 
EXPERIMENTAL and it did not work for me.

Jerry