The machines use several technological aspects to detect fake notes. Like UV detection or IR detection. This is done through the normal scanning method. A note is scanned and the pre-programmed RBI norms of elements will be compared. If there is a mismatch, it is considered a fake note. The scanning system and the advanced security features are always of the best standards in a note counting machine. However, there are times where the system may malfunction. The accuracy level may slip. There is always a percentage of error possible. It is advised to cross verify with the note once whenever the machine detects any.