[Freeswitch-dev] fax tone detection inside app

Hi, Could anyone help me how to setup the event handler within lua script? My dialplan is simply configured to execute an application for the DID range. All code processing is being happened within lua code. Now, consider the following scenario. - The call comes in - My script starts - The prompt(greeting) is being played "No one is available at a moment, please leave a message or start sending your fax now" Are there any ways, to find out at this point, whether fax negotiation has started? The following pseudo code would explain my concern: if ( getEvent("Detected-Tone") == "fax" ) doReceiveFax() else doReceiveVoice() Thanks, Peter