I know this is an old thread…but I just had an office call me and complain of the same issue.
I did some testing.
The original PDF is crystal clear.
They hit “Send a Fax” or whatever it’s called put in the phone number, attach the PDF, and hit “send”.
If you go into the outbox and click on the button to view the PDF, the PDF quality is horrible. It doesn’t matter if the resolution is set to “fine”, “superfine” or “standard”.
My guess is something on the server is converting the PDF…maybe to ensure the document size is correct…and it’s reducing the quality.
Hey, interesting timing for this thread to come up. I just saw this a couple days ago while testing fax. Setting the resolution to “superfine” and sending through UCP got me a “fine” (200dpi) resolution fax at the far end. I generated a 300dpi tiff by hand with ghostscript and sent it using the sendfax asterisk application (bypassing FreePBX) and the other side received 300dpi. So I think there is a fault in the conversion, but I haven’t had time to investigate it closely yet. There may not be much available to investigate since Fax Pro is not an open source module.