Forget everything you learned on the Internet!
Most online 'experts' recommend the following (wrong) settings:
- Reduce speed to 9600bps
- Turn off ECM error correction
Some fax machines call it 'basic' mode, others call it 'low' compatibility. Whatever it's called, you don't want it.
Instead we recommend:
- Set speed to 14,400
- Make sure ECM error correction is enabled
Sometimes these parameters are controlled together in a single option. On Brother fax machines, for example, you would need to select 'normal' compatibility at:
MENU -> 2. Fax -> 0. Miscellaneous -> 1. Compatibility -> 'normal'