Have you tried this from the Logic Controls website FAQ's;
Q. How can I set up the OPOS drivers for Microsoft RMS software?
A. We don't recommend installing Logic Controls supplied OPOS drivers for use with the RMS software, as RMS already has an integrated a special OPOS driver to work with our 3000/9000/6000 displays.
Installing our OPOS drivers may cause conflicts in certain rare cases. So, it's safer to use the special driver from RMS.
To install the OPOS driver, start the "Configure Microsoft OPOS Service Objects" program under RMS folder. Select "LineDisplay" for "Device type".
Click on "New" to create a new OPOS device name. Then click on "Configure" to set up display configuration. In setting up the configuration, "Device ID" should be set to "PD2000". Set up the COM port name that the pole display is being connected. For USB displays, virtual COM port drivers must be installed before setting up the OPOS service object. Enter the assigned COM port name (for example, "COM5") directly into the Port name text box in the OPOS display configuration.
After setting up the OPOS service object, set up the Register to use the pole display device name you have just created.