asterisk users - Mar 2005 - ADTRAN TA 750 + TE405P + PRI with problem to receive or send fax.

I have a channel bank (TA750) and a PRI with 30 channels connected to a
TE405P, in the channel bank I have a extension to a fax machine, but it
doesn't work to send or receive fax.

There are any advice ?

Kind regards,

Miguel