Hello List I see a issue with the response to an empty invite. A Panasonic PBX sends an invite with 'telephony event' mapped to type 101. Pjsip accepts this. The PBX then sends an empty invite and pjsip replies with 'telephony event' mapped to type 96 which seems to be the default. According to ticket 339 (https://trac.pjsip.org/repos/ticket/339), comment 2, pjsip is expected to send the currently active SDP. Obviously, this is not the case. Clear, the PBX should not ignore the remapped 96 but it has the right to do so, which in fact disables the 'telephony events'. Am I missing something? The attached zip contains the first negociation, which succeeds, the second which fails and the third that succeeds again Regards Martin -- Martin Schmid APS systems AG, Neumatt 4, CH-4626 Niederbuchsiten Tel direkt: +41 62 389 8891, Fax: +41 62 389 8880, Tel: +41 62 389 8888 www.aps-systems.ch