Hi Nick,
Are you trying to write to the parallel or serial port?
The "Serial Port.vi" that you are using is intended for the serial port. You are trying to wire a parallel port reference to it.
Which version of LV are you using? In LV6.x & LV7, it is recommended to use the VISA functions to communicate with through the serial port.
If you want to communicate to the parallel port, I recommend that you use the "In Port.vi" & "Out Port.vi". They are located in the Functions Palette under "Advanced" and "Port I/O".
They are really simple to use. To write to the parallel port, simply use the Out Port.vi and specify the address (ex. 0x378) and wire in the values for the data bits.
An example of this can be found in LV7, under Search Examples, Par
allel Port.
I suspect the error message you got indicates that the address value is out of range.
I got the following message when I ran your vi.
"VISA: (Hex 0xBFFF0011) Insufficient location information or the device or resource is not present in the system."
-JLV-
