Chanspy/Whisper

I need some users to be able to listen into calls for training and optimally even speak to the internal side. I can do this using chanspy but I can’t control which phone call I am listeing too or set permissions for different users.

Is there anyway to do this with some degree of ease?

This worked for me

http://hackrr.com/2013/freepbx/adding-listen-whisper-and-barge-to-freepbx-or-asterisk/#comment-33487