On a modern OS, such as Windows or Linux (preferable), you can use a virtual machine to run older DOS and such operating systems, passing the RS-232 ports of the host though to the virtual machine. Works great for me, and I use that for dealing with similar embedded systems all the time. FWIW, my preferred host OS is a clone of Red Hat Enterprise Linux (RHEL) 6, Scientific Linux (SL). CentOS is another such clone, and widely used in industry. I use SL because I personally know the maintainers of SL at Fermi National Laboratory in Illinois (my wife is a staff scientist/physicist there), so if I have an issue, I can contact them directly.
My preferred virtual machine manager tool is currently VirtualBox (open source, from Oracle/Sun), but KVM will also work very well for this. That said, I prefer the GUI and configuration tools provided by VirtualBox.