sists of three basic components, namely devices, communications network, and software and middleware. Figure 9.28 shows a M2M system architecture: Devices: These devices include embedded sensors, actuators, 14 RFID (radio frequency identification) tags and wireless modules. Smartphones and PDAs communicating through Bluetooth or WiFi can also be used. Communication Network: The communication solutions include both fixed and wireless networks. In the last few years 2.5G and 3G cellular systems have become the preferred mode of connectivity. Software and Middleware: Software includes various applications which present mean- ingful information to users about the machine network as a whole. Languages like XML (Extensible Markup Language) and Java can be used to build applications. M2M spe- cific communications protocols like BitXML (M2M communication protocol) can be used. 14 An actuator is a mechanical device for moving or controlling a mechanism or system. It takes energy, usually transported by air, electric current, or liquid, and converts that into some kind of motion. IMS, Services and Applications Machine 2G/3G (intelligent Software/ Cellular Network devices) Middleware Company Storage Figure 9.28 M2M system architecture Middleware is part of software running at the remote machines. It provides routing and buffering of data between remote machines and central IT systems (company storage area). M2M involves data transfer between numerous systems working on different platforms and obeying different protocols for data transfer, middleware in M2M allows these machines to work in their native manner, bridging protocols between different systems and manages data transfer between them. A M2M specific middleware provides various functionalities like QoS, communication scheduling and alarm triggering operations. It provides support for various real time applications like weather forecasting, remote patient monitoring and SO on. 9.12.4.2 How M2M Works Figure 9.29 shows a M2M communication setup where a machine sends its