Unlike other adapters that work for some target devices and PCs and not others, this one works for everything RS232<->USB. BUT, must be smart enough to install the drivers first (not plug&play), and look in Device Manager to see what port was assigned, or assign a different port. The nice thing is that it remembers that port for next time, so you are not chasing ports each time it is plugged in - provided that the port selected remains free on the host PC.
Unlike normal serial adapaters which you plug in and it works, this doesn't.
Response from startech.comBy Matt, Customer Support, June 27, 2019
We're sorry to hear our ICUSB2321F isn't working for you. This adapter may require drivers depending on your operating system. These drivers can be found here: https://www.startech.com/ICUSB2321F#dnlds. If you require assistance, please feel free to contact us at www.startech.com/support where our Technical Advisors are available 24-hours a day, 5-days a week.
We have several of these deployed and the Com Port Retention makes life easier for our clients - and we've never had a failure. So we are quite happy with this product.
I was unable to upgrade firmware and/or control my iOptron mount with the KeySpan Tripp-Lite USB to Serial cable. It was suggested by iOptron that I get the FIDI cable instead. A member of our Astronomy club recommended Startech.....and the rest is history. I would not hesitate using this company for additional needs.