Newbie Looking to start with RFID

HI All,

I work for a small company and we are looking to get started on using RFID systems. So far our chairman has sourced a reader which scans the RFID tags as if they are a keyboard wedge. This is fine, but this device is also supposed to have the capability to write to a tag.
I have no idea of how you write to am RFID tag.
The software that came with the reader has an SDK, which requires you to have the device set up as some kind of vitural com port.

Any help would be greatly appraicated..

Kind regards,