1. What kind of events can cause the exit of "ftdm_channel_wait" function? I've seen the "ftdm_event_type_t" that defines "FTDM_EVENT_DTMF" and "FTDM_EVENT_OOB". Is it the answer to my question?
Events such as CAS/RBS events and DTMF events if you have hardware DTMF enabled (and your hardware supports it). Given that you are using Sangoma hardware, it should work if you have a hardware DTMF enabled in the wanpipe configuration files (ie /etc/wanpipe/wanpipe1.conf)
2. Is there something that I need to do before call "ftdm_channel_wait" to enable the "events generation"?
Did you call ftdm_span_start() to start the signaling thread on the span?
Cheers,