# 7 RFID

## 7.1 Introduction

This section continues with the theme of networked devices by looking at a system of electronic tagging known as Radio Frequency Identity (RFID). In this system, an electronic tag is attached to an object (for example, the pin described in the The Road Ahead extract in the previous section) and an RFID reader is used to interrogate the tag wirelessly and receive information stored on it. We are using the word 'interrogate' here because the reader sends out a signal and the tag responds with its data in a question-and-answer type of exchange. The signals passing between the tag and the reader are radio frequency signals – hence the description 'RFID' to describe this type of technology.

At its simplest level, the information held on the tag is an identity code, which may be used as a reference to information stored in a database. The RFID reader transmits the tag's information to a host computer for processing. Or the tag could store information about the object it is attached to – for example, its weight, price, date of manufacture, etc.

In a fast-moving field like IT, the Web provides a key resource for keeping yourself updated on new developments. Activities in this and the next section will provide you with opportunities to search for and identify relevant information from third-party sources and to develop the skill of presenting, in your own words, the information you find.

'Third party' is a term borrowed from the legal profession in the context of contracts between two parties – for example a policyholder and an insurance company. The policyholder is referred to as the first party, the insurance company as the second party, and anyone else as the third party. Were you to signt a learning 'contract' with The Open University, you would be the first party, The Open University the second party, and anyone else the third party. So when we refer to 'third-party sources' we are referring to any sources originating elsewhere.

OpenLearn - IT: device to device communication
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