RFID stands for Radio Frequency IDentification. It typically applies to a technology that uses radio waves to automatically identify people or objects. While there are various ways to identify, the most common is to store a serial number that represents a person or object identity and possibly other information, on a microchip that is attached to an antenna. Collectively the microchip and antenna represent a RFID transponder or an RFID tag. The antenna gives the chip ability to transmit identity information to a RFID reader. Then the RFID reader converts the radio waves into digital information that can then be passed to the computer for usage. RFID has been around since the 1970s.
Since the radio waves from the low end of the electromagnetic spectrum, waves are safe as radio waves from a car radio.
RFID and Bar codes are different technologies and have different applications. The big difference between the two is bar codes are line-of-sight technology. A scanner requires a bar code be brought towards a scanner in order for it to be read. RFID on the other hand, doesn’t require line of sight. RFID tags can be read as long as they are within range of a RFID reader. If a label is somehow removed or damaged there is no way to scan the item.