I have this line in my dial plan:

<action application="set" data="execute_on_answer=spandsp_start_fax_detect transfer 'FAX_DETECTED XML default' 10"/>

However, the fax is not detected at times. There is one particular fax machine that freeswitch never detects the fax tone. When I listen to the pcap, I do hear the fax tone.

Is there anything I can do to improve the fax tone detection?

Thanks,

Ali Pey