RFID technology uses a RF field from a reader to energise the transponder (card, tag or fob). The energised transponder sends a RF reply to the reader. The transponder reply is a digital data stream.
Low Frequency ID (LF RFID) Operating at a low RF frequency this technology offers longer read range.
High Frequency ID (HF RFID) High frequency RF ID technology allows more data to be transfered when the transponder is read.