USB-to-serial adapters are not all created equally. If you buy one that is not Windows Logo Certified for your particular OS version, you may save $5. But those that are logo certified and listed on the Microsoft Hardware
Qualification List (HCL) for the OS have been extensively tested and are known to work most if not all of the time.
IBM and Keyspan are two of the brands that are no more expensive than any others, logo certified models since USB first shipped.
Or, you can skip the logo certification
, and if you're lucky the five bucks you saved will come back to bite you. Even if it works now--it may not work with the next device, or next program.