Some received faxes partially print

[BobNYC]

Very frustrated with Digital Voice when it comes to my fax machine.  Many faxes only print about 20% of the page.  I have lowered baud rate to 9600, turned off error correction and put a DSL filter in the DV phone line...all suggestions I've read here.  Nothing works.  Any suggestions?

BYW, it's an HP 7780 All-In-One machine that worked perfectly on copper phone line.