Beep to notify successful attended transfer

[Ret]

Sorry to bring such an old post. I still think this is a feature many people is waiting for!
Asterisk implements its own method to transfer calls (*2) That is why we get the beep sound.

Yealink phones rely only on SIP protocol (http://www.in2eps.com/fo-sip/tk-fo-sip-service-05.html) so they don't execute Asterisk code *2 to start a transfer and we don't hear the beep.

I think Yealink could still implement a beep sound after transfer: The phone receiving the transfer (or the one being transferred) could play a beep sound on their RTP session because it was established by a REFER SIP packet.

Please try this for next firmware!