Bluetooth is capable of passing through solid objects, including walls.
This means it can be used as soon as the distance separating the two devices to be connected is less than or equal to the supported range, without any further considerations regarding orientation or line of sight. However, if a Bluetooth device moves out of range from the other, the connection automatically disconnects. All Bluetooth-equipped devices in a work environment are capable of generating small wireless networks, i.e., an interconnection of data communications such as a computer network (LAN). Unlike a LAN, the interconnected devices are not limited to computers but include other various electronic devices such as cell phones, headphones, projectors, scanners, video cameras, cameras, and various household appliances. These small wireless networks are generally called Piconets. A piconet consists of two or more peripherals sharing a communication channel using Bluetooth, up to a maximum of 8 devices. The 2.4 GHz frequency is below the amateur radio UHF frequencies which range from 5.65 – 5.85 GHz. The Bluetooth communication system is designed to operate even in environments with strong interference, electromagnetic fields, what is known as electrosmog, to ensure consistently efficient and reliable connections. For example, it is possible to listen to music from a stereo system or TV via wireless headphones even if there are objects or obstacles in between, something impossible with infrared (IrDA) headphones. Devices equipped with this technology thus communicate with each other by dynamically creating and reconfiguring (the configuration changes automatically when a device is added or removed) ad hoc networks (the piconets) composed of up to eight nodes (multiple piconets can in turn interconnect, increasing expansion possibilities). This allows, for example, synchronizing data between a laptop and a PDA simply by bringing the two devices close together, or automatically switching to hands-free mode when entering a car while talking on the phone. All this is possible thanks to the “Service Discovery Protocol” (SDP), which allows a Bluetooth device to determine which services other devices present in the piconet provide. This protocol can act both as a Server (i.e., it can be queried by another device and respond with its own services) and as a Client (querying other devices), and each device holds information about the services it supports and the protocols it can use: other devices can use this information to determine the interaction possibilities with nodes in the piconet. This is necessary because, naturally, a Bluetooth printer will not offer the same functionalities as a PDA or a headset, so each node must know the functions and capabilities of every other node in the network. For a concrete example, if a Bluetooth phone wants to transfer a text message to a PDA, it can query the PDA to see if it has email functionality or can receive text in another way. Additionally, when a device joins a piconet for the first time, it will perform a “scan” of all present nodes to understand how it can interact with them. Regarding power, Bluetooth devices are distinguished by classes: class 1, 2, 3. Generally, a notebook implements a class 2 Bluetooth terminal with a range of several meters. The Bluetooth standard allows the creation of WPANs (Wireless Personal Area Networks) with various new services. These are defined as “individual wireless networks,” i.e., groups of different devices connected to meet the needs of the individual. Bluetooth, in fact, allows managing both data and voice, using packet transmission on a radio network for data and a connection-oriented mode for voice.
Pubblicato in Digital Tools, Video
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