OPOS drivers should already be installed on the terminal when it ships if required, BUT if not, you may need to install OLE for Retail -
OPOS_CCOs_1.13.003.msi
Once done, you can either use an OPOS Utility to configure LDN's (Local Device Names) or you may likely need to handle the changes directly in the registry...
Run 'Regedit' and look for the keys at 'HKEY_LOCAL_MACHINE\SOFTWARE\OLEforRetail\ServicesOPOS'
If you expand the headings, you can see any OPOS Device Drivers installed. These have to be installed for the appropriate machine so they know how to operate, but the LDN's have to match for the software being used. The example below shows what you should see...
ICR For Example offers
2x Cash Drawers - These Need to have LDN's of 'Cash Drawer' and 'Cash Drawer 2'
1x Line Display - This Needs to have LDN of 'Line Display'
6x Printers - These Can be 'Printer 1' , 'Printer 2', etc
Note the Capital Letters - OPOS is CaSe SenSAtiVe
To Set the Line Display for example :-
Open LineDisplay Key and Create a String value for the LDN - 'Line Display' and the Value needs to be the Device Drivers Folder 'DM-D110' for this one.