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Piconet
A piconet is an ad hoc network that links a wireless user group of devices using Bluetooth technology protocols. A piconet consists of two or more devices occupying the same physical channel (synchronized to a common clock and hopping sequence). It allows one ''master'' device to interconnect with up to seven active ''slave'' devices. Up to 255 further slave devices can be inactive, or ''parked'', which the master device can bring into active status at any time, but an active station must go into parked first. Some examples of piconets include a cell phone connected to a computer, a laptop and a Bluetooth-enabled digital camera, or several PDAs that are connected to each other. Overview A group of devices are connected via Bluetooth technology in an ad hoc fashion. A piconet starts with two connected devices, and may grow to eight connected devices. Bluetooth communication always designates one of the Bluetooth devices as a main controlling unit or ''master'' unit. Other devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scatternet
A scatternet is a type of ad hoc computer network consisting of two or more piconets. The terms "scatternet" and "piconet" are typically applied to Bluetooth wireless technology. Description A ''piconet'' is the type of connection that is formed between two or more Bluetooth-enabled devices such as modern cell phones. Bluetooth enabled devices are "peer units" in that they are able to act as either master or slave. However, when a piconet is formed between two or more devices, one device takes the role of the 'master', and all other devices assume a 'slave' role for synchronization reasons. Piconets have a 7 member address space (3 bits, with zero reserved for broadcast), which limits the maximum size of a piconet to 8 devices, i.e. 1 master and 7 slaves. A ''scatternet'' is a number of interconnected piconets that supports communication between more than 8 devices. Scatternets can be formed when a member of one piconet (either the master or one of the slaves) elects to particip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bluetooth
Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limited to 2.5 milliwatts, giving it a very short range of up to . It employs UHF radio waves in the ISM bands, from 2.402GHz to 2.48GHz. It is mainly used as an alternative to wire connections, to exchange files between nearby portable devices and connect cell phones and music players with wireless headphones. Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 35,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks. A manufacturer must meet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Area Network
A personal area network (PAN) is a computer network for interconnecting electronic devices within an individual person's workspace. A PAN provides data transmission among devices such as computers, smartphones, tablets and personal digital assistants. PANs can be used for communication among the personal devices themselves, or for connecting to a higher level network and the Internet where one master device takes up the role as gateway. A PAN may be wireless or carried over wired interfaces such as USB. A wireless personal area network (WPAN) is a PAN carried over a low-powered, short-distance wireless network technology such as IrDA, Wireless USB, Bluetooth or ZigBee. The reach of a WPAN varies from a few centimeters to a few meters. WPANs specifically tailored for low-power operation of the sensors are sometimes also called low-power personal area network (LPPAN) to better distinguish them from low-power wide-area network (LPWAN). Wired Wired personal area networks provide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ad Hoc Network
An ad hoc network refers to technologies that allow network communications on an ad hoc basis. Associated technologies include: *Wireless ad hoc network *Mobile ad hoc network *Vehicular ad hoc network **Intelligent vehicular ad hoc network * Protocols associated with ad hoc networking **Ad hoc On-Demand Distance Vector Routing **Ad Hoc Configuration Protocol * Smart phone ad hoc network *Ad hoc wireless distribution service Ad hoc Wireless Distribution Service (AWDS) is a layer 2 routing protocol to connect mobile ad hoc networks, sometimes called wireless mesh networks. It is based on a link-state routing protocol, similar to OLSR. Principle of operation AWDS use ... References Computer networking {{networking-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wireless User Group
Wireless community networks (WCNs) or wireless community projects or simply community networks, are non-centralized, self-managed and collaborative networks organized in a grassroots fashion by communities, NGO's and cooperatives in order to provide a viable alternative to municipal wireless networks for consumers. Many of these organizations set up wireless mesh networks which rely primarily on sharing of unmetered residential and business DSL and cable Internet. This sort of usage might be non-compliant with the terms of service of local internet service provider (ISPs) that deliver their service via the consumer phone and cable duopoly. Wireless community networks sometimes advocate complete freedom from censorship, and this position may be at odds with the acceptable use policies of some commercial services used. Some ISPs do allow sharing or reselling of bandwidth. The First Latin American Summit of Community Networks, held in Argentina in 2018, presented the following defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Master (device)
Master/slave is a model of asymmetric communication or control where one device or process (the "master") controls one or more other devices or processes (the "slaves") and serves as their communication hub. In some systems, a master is selected from a group of eligible devices, with the other devices acting in the role of slaves. The ''master/slave'' terminology was first used in 1904. Since the early 21st century, the terms have become a subject of controversy from their association with slavery and some organizations have opted to replace them with alternative terms. Examples * In electronics, master/slave relationships are used to describe some of the following scenarios: ** In parallel ATA hard drive arrangements, the terms master and slave are used to describe drives on the same cable, but neither drive has control or priority over the other. ** A master clock that provides time signals used to synchronize one or more slave clocks as part of a clock network. ** In AXI, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slave (device)
Master/slave is a model of asymmetric communication or control where one device or process (the "master") controls one or more other devices or processes (the "slaves") and serves as their communication hub. In some systems, a master is selected from a group of eligible devices, with the other devices acting in the role of slaves. The ''master/slave'' terminology was first used in 1904. Since the early 21st century, the terms have become a subject of controversy from their association with slavery and some organizations have opted to replace them with alternative terms. Examples * In electronics, master/slave relationships are used to describe some of the following scenarios: ** In parallel ATA hard drive arrangements, the terms master and slave are used to describe drives on the same cable, but neither drive has control or priority over the other. ** A master clock that provides time signals used to synchronize one or more slave clocks as part of a clock network. ** In AXI, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture and, therefore, mobile telephones are called ''cellular telephones'' or ''cell phones'' in North America. In addition to telephony, digital mobile phones ( 2G) support a variety of other services, such as text messaging, multimedia messagIng, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, video games and digital photography. Mobile phones offering only those capabilities are known as fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Camera
A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices like smartphones with the same or more capabilities and features of dedicated cameras (which are still available). High-end, high-definition dedicated cameras are still commonly used by professionals and those who desire to take higher-quality photographs. Digital and digital movie cameras share an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit a controlled amount of light to the image, just as with film, but the image pickup device is electronic rather than chemical. However, unlike film cameras, digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory. Many digital cameras can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Digital Assistant
A personal digital assistant (PDA), also known as a handheld PC, is a variety mobile device which functions as a personal information manager. PDAs have been mostly displaced by the widespread adoption of highly capable smartphones, in particular those based on iOS and Android. A PDA has an electronic visual display. Most models also have audio capabilities, allowing usage as a portable media player, and also enabling many of them to be used as telephones. Nearly all modern PDAs can access the Internet, intranets or extranets via Wi-Fi or Wireless WANs, letting them include a web browser. Sometimes, instead of buttons, PDAs employ touchscreen technology. The first PDA, the Organiser, was released in 1984 by Psion, followed by Psion's Series 3, in 1991. The latter began to resemble the more familiar PDA style, including a full keyboard. The term ''PDA'' was first used on January 7, 1992 by Apple Inc. CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilobit
The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix ''kilo-'' (symbol k) is defined in the International System of Units (SI) as a multiplier of 103 (1 thousand), and therefore, :1 kilobit = = 1000 bits. The kilobit has the unit symbol kbit or kb. Using the common byte size of 8 bits, 1 kbit is equal to 125 bytes. The kilobit is commonly used in the expression of data rates of digital communication circuits as kilobits per second (kbit/s or kb/s), or abbreviated as ''kbps'', as in, for example, ''a 56 kbps PSTN circuit'', or ''a 512 kbit/s broadband Internet connection''. The unit symbol kb (lowercase 'b') is typographically similar to the international standard unit symbol for the kilobyte, i.e. kB (upper case 'B'). The International Electrotechnical Commission (IEC) recommends the symbol bit instead of b. The prefix ''kilo-'' is often used in fields of computer science and information technology wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE 802
IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LAN), personal area network (PAN), and metropolitan area networks (MAN). The IEEE 802 LAN/MAN Standards Committee (LMSC) maintains these standards. The IEEE 802 family of standards has had twenty-four members, numbered 802.1 through 802.24, with a working group of the LMSC devoted to each. However, not all of these working groups are currently active. The IEEE 802 standards are restricted to computer networks carrying variable-size packets, unlike cell relay networks, for example, in which data is transmitted in short, uniformly sized units called cells. Isochronous signal networks, in which data is transmitted as a steady stream of octets, or groups of octets, at regular time intervals, are also outside the scope of the IEEE 802 standards. The number 802 has no significance: it was simply the next number in the sequence that the IEEE used for standards projects. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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