Advice with sending faxes


I set up asterisk to send faxes and it works fine in general.
I have however many times a problem with faxes that are more then 6-8pages. It sends only the first page!
I though first it is related to tiff conversion, so I sent to asterisk a fax and took the tiff file created by rxfax. It failed to send also THIS tif file created by rxfax.
I played with the gain ? txgain in zapata.conf but no help.
All echo cancel in zapata.conf are set to NO
Could be a zap driver issue? Any one has better experience with newer versions?

We use spandsp and txfax and rxfax applications.
We use an analog Digium TDM400 to snd/rcv faxes.



The final line is that * works with faxes but is not reliable.
Need to wait for a solution that implements T.38.