First, check to see whether a driver exists already in labview. Most times they will have a gbip driver. Then you need to convert it to a serial driver.
Modifying a lab view driver is not that hard. I have gotten quite good at it by now. The biggest differences between gpib and serial (you will be using serial to communicate with your device if it is plugged in via gpib to usb) is the line endings and data limits. I found that everything I sent to the devices had to be terminated by a carrige return, and I had to modify the read driver to read untill there was no more data left. Apparently, gpib will let you get all the data that was sent to the pc in one read. With serial, this is not the case. You have to read however much is on the serial port, wait a few ms, then continue untill there is nothing left to read. I just created new subvi's for read and write to do these two things. I can send them to you if you want.
Eric
