ECP/EPP are MUCH faster than SPP, so I would highly recommend setting that mode. It would take 6 minutes to scan a page on my mom's computer that had an ISA LPT card with only SPP mode but only 30 seconds on my brother's computer with ECP+EPP. Shouldn't be as bad for printers, but it can still be a noticable difference - you might try experimenting.

Also, about the tickbox: it's possible that the tickbox is only there for backwards compatability with SPP LPT ports that have problems with bi-directional communication.

Thank you very much for your suggestions. I will leave it at the maximum speed setting (ECP+EPP) because it seems to work just fine. 😎

ECP takes an IRQ or DMA or both. Not sure which but that is why I stick to EPP 1.9. If you have some sort of accessoire that uses the prnter port there is a big difference. Printing is not as heavily affected.

ECP (Extended capabilities port?) uses a DMA channel. In my case, DMA 3, which seems very common for ECP.

Now I remember experiencing a difference. When using an older IOMEGA ZIP drive (external and parallel, of course). Having EPP or ECP would make QUITE a difference. For printers I still don't notice a difference and nowadays, even less, more printers are coming in some USB 2.0 flavour.

The printer must also be ECP/EPP capable for higher speeds.

Link to info on Google Groups

Nice info. My printer is listed as IEEE 1284.4 (WinXP hardware manager)- I better left the port at ECP mode.

UPDATE:

Fixed the bi-dir compatibility. It seems Microsoft's WinXP built-in PS driver doesn't support bi-directional communication for the port. I just installed the HP driver. 😎

UPDATE2:

Using bi-dir in the port, decreases waiting time twice or three times. Neat.