thanks
ESXi does not directly support serial or parallel ports. Refer to http://kb.vmware.com/kb/1003129
You can use virtual ports as in the KB article or network attached ports. I haven't looked for a while but network attached devices have been available. Depending on what the port is used for you might try a network attached USB device and a USB to parallel adapter.
big problem
I have software that requires a license key parallel!
I can configure a card based on my ESXi host
I would contact the software company to see if they can recommend a workaround. There is software available that can redirect serial ports and possibly parallel ports over tcp/ip.
The ability to add serial / parallel and USB ports in ESXi is for supporting virtual ports and is not for supporting physical devices. An upcoming release of ESXi will help.
thank you very much