Making USB using RS232 converter works really well with all the devices I tried.
USB to RS232 converter can also use FT8U232AM and Maxim-IC MAX235

If no FT8U232AM, could also use TTL level RS232 signals.

The FT8U232AM and supporting components are also available as a complete module – called USBMOD1 – in 32pin DIL IC packages, making the whole project is very easy to make.

Making USB using RS232 converter

Making USB using RS232 converter