COM & LPT Ports

[tonster]

This question may seem basic, but I am confused with regards to com/lpt ports. If you disable them in the bios, sometimes windows finds them at the default irq/memory. Sometimes, you must enable them for a device to use them. I have even had situations where the bios would automatically re-enable them with really weird configs (on an IBM). I am not sure exactly how this works, and why these situations occur with com ports. I feel I have a decent grasp of hardware, however, everytime I try something to make a modem work, I get confused. I understand that usually com 1/3 correspond to pci slots 1 & 3 respectively, and com 2/4 correspond to 2 & 4. Anyway, if someone could clear up the com port fiasco for me, I would appreciate it.
Additionally, I have an LPT port that will NOT work with bidi. I am not sure what could causing it to not work bidirectionally with a plotter, but it flat won't print with bidi enabled in the bios.

 

[DaddyG]

OK, your com ports should correspond with any PCI slots. COM1 and COM3 share IRQ 4 and COMM 2 and COMM 4 share IRQ3. (Note that they don't share very well so if you can avoid comm pprt sharing. do it). If you use an internal modem then and ps/2 or USB mouse, your COMM ports can be disabled in your BIOS. If you use an external modem, enable the comm port that you attach the modem to AND set the IRQ to Legacy ISA device in your BIOS PCI/PlugnPlay. This will stop Winblows sharing the IRQ with any other device.

On to your LPT issues, bidi is a strange option, the options are normally EPP/ECP, and when you set the options you usually need the special IEE cable (can't remember the # ).