What are recommended parameters for faxes?
A. Some applications require a DataGlyph to survive two cycles through a fax machine. That can introduce a lot of degradation, but several strategies can help. First, try to make the marks themselves look as good as possible after transmission. If possible, use an electronic source for the first transmission, and match the DataGlyph image resolution against the fax transmission resolution. Also, make the glyphmarks large to overcome distortion by poor quality fax printers and to avoid descreening algorithms from fax machines that try to be too clever. For best results, meet or exceed a 7×7 pixel default cell size in the final image. Second, make sure you use a generous quantity of ECC, so that the DataGlyph can decode even if many marks are destroyed. A 25% ECC is very generous for most applications, but can be raised for extremely noisy conditions. Both cellsize and ECC parameters make a tradeoff between reliability vs. data density, so find a balance that works for your application.
