Hello Rafal.

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I don't know what is the exact difference between a pre-answerred and answerred call but one nice thing is that when you <hangup /> or <break /> in this state the call will be rejected and the caller will hear a 'busy' signal.

You are dealing with early_media.
https://wiki.freeswitch.org/wiki/Early_Media

This is what "normally" your mobile operator uses to say stuff like , your are low on credit or , voicemail like messages at least here in Europe is pretty common.

You can generally "play" with this feature inside the LAN but it your are using PSTN / GSM Networks take into consideration that the provider will generally drop your early media . Again this depends on your provider Config if its Tier 1 , 2 ,3 ....

Antonio

On 6/27/13 11:52 AM, Rafal Gwizdala wrote:
I don't know what is the exact difference between a pre-answerred and answerred call but one nice thing is that when you <hangup /> or <break /> in this state the call will be rejected and the caller will hear a 'busy' signal.