Call queue without picking up the handset (as when the subscriber is busy on 3g) in FreeSwtich, how?

Question

FreeSWITCH

There is an incoming trunk from free of charge, distribution by subscribers is configured for free, one of which registers FS, which also has several subscribers (but so far one). It is necessary to make it so that at the second call the subscriber hears beeps or something else, while at the end of the conversation with the first, the call reaches the FreeSwitch user. I would do FIFO or ModCallCenter but they pick up the phone. Is it possible to ?

Answer 1

In order not to pick up the phone (there was no count of seconds), it is necessary that the call be in the pre-answer state (not 180, but 183) - another word to search - "early media" - https://wiki.freeswitch.org/wiki/ Early_Media
And the fact that you paint this is a regular queue - you can configure it through the Call Center