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