Get a real serial port or a FTDI Chipi-X line level serial adaptor.
Also get a DB9 to DB25 adaptor or make your own. Pinout:
Get the DOS utilities disk HERE and extract "495XPCUtil_D1.zip" to a DOS directory.
Download / apt-get DosBox
Create a dosbox.conf file in the DOS directory:
[serial] serial1=directserial realport:ttyUSB0 [autoexec] mount C "." C: dir
This will automatically load the current folder as C and display it to you so you know it's mounted.
The serial port may be different for you, I'm on linux with an FTDI adaptor so ttyUSB0 for me.
Now all you need to do is run 5XREMOTE.EXE and you can communicate with your 4952.
1 - Run '5XREMOTE.EXE'
2 - Enter 9600 as the Baud Rate
3 - 'Delete Slave's Application Module'
4 - 'Download Application Module'
5 - 'Execute Slaves Application Module'
If you did a cold boot then you can skip step 3, otherwise you need to delete the old app before you can upload a new one.
NOTE: On linux machine dosbox IS case sensitive. DOS is not case sensitive so its a bit of an annoying issue. When you load your app the interface only allows upper case names and it provides the .APP for you. You need to make sure your programs are uppercase as well as the extention or else it won't find them.