How to detect voice (human/machine) on DAHDI channel

Hello all,

This is related to my previous post @ http://forums.digium.com/viewtopic.php?f=1&t=81935&p=170673&sid=cce9bde8a4e8a1d5d92a3bfca4dd5645&sid=f14cf8992b310cfbb7f302768fa72c98#p170673.

I need to know, is there is a way in the dialplan to detect human or machine voice? I have already being using AMD for answering machine/voicemail detection but its results are not so appreciating. So are there any other way to detect.

My original problem is stated in the post above.