Asterisk incoming fax autodetection

i need help for set asterisk to detect in auto the incoming fax.

I try a lot of configuration but when i send a fax to asterisk the call is redirect to my int number and in the log i saw the report : nofax
i have an x100p card for the first configuration step but in the future i’ll want buy an td400p digium.
is configuration wrong?
is card?

please help me

Sorry for my english.

Could you post the content of your zaptel, zapata and extensions.conf files?