cm 4730 fax problem

[Max]

I have a cm 4730 that takes 1 hour plus to send 10 pages via fax. The fax line is routed via a network point and there is no ather fax to try or move the machne next to master BT socket. Had the formatter out and the fax option card.
Upgraded the f/w. The line sounds fine no noise that i can hear.I tried with and without ecm and dropped the speed to 14000 bps still no change. Any sudgestions??