Is there any issue with standard RFID scanners which send scanned information via USB either emulating RS-232 protocol or keyboard?
My 2 cents:
As far as I understand, everything neede to receive from a scanner is scanned code as sequence of digits – which all scanners send in one of above mentioned forms (or in some other more exotic protocols).
in case when when characters arrive from the keyboard, these are visible from any app (not always the best thing)
in case when when characters arrive from RS-232, these are visible only for app which opened given COM port (this sounds better)
Some RFID scanners allow to set few other things, for example fixed prefix and suffix of scanned sequence (e.g.
if this is possible, it is clearly documented in the manual (and settable in simple way where no special API is needed)
generally this is quite useless unless you have more than one scanner attached to the machine
I haven't found satisfactory solution for USB keyboard emulation scanners so far (neither barcode nor RFID). If scanned characters arrive, any active application gets them as if they were typed by user. You cannot easily distinguish which device has actually sent them until you descend to some lower layers of system. I also still need to do a research on this, but as fast solution I recommend RS-232. (Or instructing your users to have your application active just before they scan anything.) This is possible starting point for mentioned research.