A colleague has several new Isel machines bought, and he has the same experience. The machine is too old, the SW is outdated, but you can buy the new for several grand and so on. But iirc Kay comes from a different supplier, so ask the firm if they can offer a test, a serial port is not really a problem.
You can add a PCI card or if you want to buy a new computer, there are many
who have a serial port in it. And eventually an adaptercable from USB to serial is also working.