|If the printer works properly in EPP mode, then don't use ECP mode if it won't work properly in that mode.|
There is very little difference in performance of EPP mode vs. ECP mode, and EPP mode does not require that a DMA channel is available - sometimes there is no free DMA channel available for ECP mode, even when you have more than one choice when you choose ECP mode in the bios Setup. .
The parallel printer cable must support IEEE1284 specs.
Either IEEE1284 must be printed on the cable or the end connectors, or the individual wires inside the unmarked cable must have the minimum wire gauge required for IEEE1284 or better. If the wire gauge is printed on the cable, e.g. 18 AWG, the lower that number, the thicker - greater diameter - of the individual wires inside the cable.
The thicker the unmarked cable, the thicker the individual wires inside the cable are, the more likely it will support IEEE1284 specs. E.g. older unmarked heavy duty parallel printer cables support IEEE1284 specs fine.