Hello, With #2018, @nanang introduces support for DTLS-SRTP. https://trac.pjsip.org/repos/ticket/2018 #2018 (Support DTLS for SRTP keying) – pjsip Open source ... trac.pjsip.org DTLS-SRTP is an SRTP keying method that uses media channel for SRTP key negotiation which is secured using TLS. As SRTP key negotiation is done in media channel ... The ticket states: <<In generating SDP answer, SRTP will automatically detect and match the keying method to the SDP offer's, e.g: if remote sends offer using DTLS-SRTP, we will start DTLS nego immediately and answer using DTLS-SRTP too.>> I am unable to get pjsua to answer a DTLS-SRTP call. Instead, I get a 406: not acceptable response. I have attached  340_dtls-srtp_offer_accepted.py, a test demonstrating the behaviour I was expecting. This test is to be placed in tests/pjsua/scripts-sendto in r5621 or higher (I am on r5646). Regards, Marcel This email is security checked and subject to the disclaimer on web-page: http://www.capita.co.uk/email-disclaimer.aspx