Hi, Our scenario is the following: A leg: Verto client - FS server B leg: FS server - SIP phone Sending dtmf in the direction from A leg to B leg works, but during the same call, sending dtmf in the opposite direction doesn't. More precisely, on the B leg we have dtmf of type rfc2833. It can be seen from logs, that after receiving dtmf from the SIP phone, the io_routine rtc_send_dtmf() of mod_rtc is called. Our aim is to send dtmf in JSON to Verto client the same way as it works in the direction from A leg to B leg. To solve our issue, we tried to add the io_routine verto_send_dtmf() to mod_verto.c, but it was not called. Could you help us, please? Thanks in advance, Andrea Balog-Bartos