Dear eyup yilmaz!
When you have several devices working in keyboard mode, in general there is no way to distinguish the output of one device from that of another device. It all comes from keyboard.
You can use a trick: add a particular prefix to the output of a particular device. Say, the "#" prefix for your RFID reader, and the "*" prefix for your barcode scanner. As a result, you will be able to see what comes from which device.