Incase the ECP mode is enabled on the parallel port, look out for resource conflicts and incompatibilities. There are chances that few devices may not work properly when this mode is turned ON, as the software or hardware is not compatible. It is advisable to disable this setting to isolate the problem.
Further, this mode usually requires the use of a DMA channel. Usually DMA1 is the default channel chosen, which is the default for many sound cards too. In such cases, try changing it to DMA 3 when in ECP mode.
In cases where the printer needs bi-directional communication for its driver software to work properly, make sure that the parallel port is set to "enable" bi-directional mode. This often means setting the port to bi-directional or EPP mode.
If multiple parallel ports (i.e., LPT2 or LPT3 in place of the LPT1 that is more common) are being used, then you need to crosscheck and be sure that they are configured with correct resources.
