An RFID reader is an active device that uses radio frequency to read information contactless from a data carrier like an RFID tag. Most of the readers are also able to function as write units. Typically, RFID reading devices contain a microprocessor or digital signal processor. An RFID reader is equipped with an internal or external antenna that grabs the information from the RFID tags. The data is then passed on by the reader to a communication unit that transmits the information via interfaces to an external host system which allows the interpretation of mass data or the targeted search for certain tagged pieces.