Hello,
There are a couple possiblities I think:
1. If you have an RS-422 interface on your computer, they likely provided a dll from which you can make calls from CVI.
2. If the 422 interface on your computer shows up in Measurement and Automation explorer, then it is likely that it populates as a COM port just as most serial interfaces do, and you can try using NI-VISA calls. NI-VISA will call into the appropriate driver for multiple interfaces, such as serial, gpib, etc.
Repost with any further questions or updated information!
Thank you,
JLS