On the second settings page, theres an impedance setting, but no power settings that I've come accross... The closest thing I can find is "Powerline Ring Tone", and "Volume Amplification". I could look up the REN of the fax machine, but I'm sure it's quite low (meaning it shouldn't require any more current than a regular phone).

I should also have stated that the fax machine can't dial, either, the ATA acts like it isn't hearing the tones.