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Power Over Data Lines
Power over Ethernet (PoE) describes any of several standards or ad hoc systems that pass electric power along with data on twisted-pair Ethernet cabling. This allows a single cable to provide both a data connection and enough electricity to power networked devices such as wireless access points (WAPs), IP cameras and VoIP phones. Techniques There are several common techniques for transmitting power over Ethernet cabling, defined within the broader Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard since 2003. The three techniques are: *''Alternative A'', which uses the same two of the four signal pairs that 10BASE-T and 100BASE-TX use for data in typical Cat 5 cabling. *''Alternative B'', which separates the data and the power conductors for 10BASE-T/100BASE-TX, making troubleshooting easier. *''4PPoE'', which uses all four twisted pairs in parallel, increasing the achievable power. ''Alternative A'' transmits power on the same wires as data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethernet Over Power
Power-line communication (PLC) is the carrying of data on a conductor (the ''power-line carrier'') that is also used simultaneously for AC electric power transmission or electric power distribution to consumers. A wide range of power-line communication technologies are needed for different applications, ranging from home automation to Internet access, which is often called broadband over power lines (BPL). Most PLC technologies limit themselves to one type of wires (such as premises wiring within a single building), but some can cross between two levels (for example, both the distribution network and premises wiring). Typically transformers prevent propagating the signal, which requires multiple technologies to form very large networks. Various data rates and frequencies are used in different situations. A number of difficult technical problems are common between wireless and power-line communication, notably those of spread spectrum radio signals operating in a crowded environm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phantom Power
Phantom power, in the context of Professional audio, professional audio equipment, is Direct current, DC electric power equally applied to both signal wires in Balanced line, balanced microphone cables, forming a phantom circuit, to power microphones that contain active electronic circuitry. It is best known as a convenient power source for condenser microphones, though many active DI unit, direct boxes also use it. The technique is also used in other applications where power supply and signal communication take place over the same wires. Phantom power supplies are often built into mixing consoles, microphone preamplifiers and similar equipment. In addition to powering the circuitry of a microphone, traditional condenser microphones also use phantom power for polarizing the microphone's transducer element. History Phantom powering was first used for copper wire-based landline, telephone landlines since the introduction of the rotary dial telephone in 1919. One such applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classic Ethernet
The early generation of Ethernet standards had a maximum throughput of . In 10BASE-X, the 10 represents its maximum throughput of , BASE indicates its use of baseband transmission, and X indicates the type of medium used. Classic Ethernet includes coax, twisted pair and optical variants. The first Ethernet standard was published in 1983 and classic Ethernet operating at was the dominant form of Ethernet until the first standard for Fast Ethernet was approved in 1995. Varieties Fibre-based standards (10BASE-F) ''10BASE-F'', or sometimes ''10BASE-FX'', is a generic term for the family of 10 Mbit/s Ethernet standards using fiber-optic cable. In 10BASE-F, the 10 represents a maximum throughput of 10 Mbit/s, BASE indicates its use of baseband transmission, and F indicates that it relies on a medium of fiber-optic cable. The technical standard requires two strands of 62.5/125 μm multimode fiber. One strand is used for data transmission while the other is used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1000BASE-T1
In computer networking, Gigabit Ethernet (GbE or 1 GigE) is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in 1999, and has replaced Fast Ethernet in wired local networks due to its considerable speed improvement over Fast Ethernet, as well as its use of cables and equipment that are widely available, economical, and similar to previous standards. The first standard for faster 10 Gigabit Ethernet was approved in 2002. History Ethernet was the result of research conducted at Xerox PARC in the early 1970s, and later evolved into a widely implemented physical and link layer protocol. Fast Ethernet increased the speed from 10 to 100 megabits per second (). Gigabit Ethernet was the next iteration, increasing the speed to . The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z, and required optical fiber. 80 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
100BASE-T1
In computer networking, Fast Ethernet Ethernet physical layer, physical layers carry traffic at the nominal rate of . The Classic Ethernet, prior Ethernet speed was . Of the Fast Ethernet physical layers, 100BASE-TX is by far the most common. Fast Ethernet was introduced in 1995 as the IEEE 802.3u standard and remained the fastest version of Ethernet for three years before the introduction of Gigabit Ethernet. The acronym ''GE/FE'' is sometimes used for devices supporting both standards. Nomenclature The ''100'' in the media type designation refers to the transmission speed of , while the ''BASE'' refers to baseband signaling. The letter following the dash (''T'' or ''F'') refers to the physical medium that carries the signal (twisted pair or fiber, respectively), while the last character (''X'', ''4'', etc.) refers to the line code method used. Fast Ethernet is sometimes referred to as 100BASE-X, where ''X'' is a placeholder for the FX and TX variants. General design Fast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
10GBASE-T
10 Gigabit Ethernet (abbreviated 10GE, 10GbE, or 10 GigE) is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE 802.3ae-2002 standard. Unlike previous Ethernet standards, 10GbE defines only full-duplex point-to-point links which are generally connected by network switches; shared-medium CSMA/CD operation has not been carried over from the previous generations of Ethernet standards so half-duplex operation and repeater hubs do not exist in 10GbE. The first standard for faster 100 Gigabit Ethernet links was approved in 2010. The 10GbE standard encompasses a number of different physical layer (PHY) standards. A networking device, such as a switch or a network interface controller may have different PHY types through pluggable PHY modules, such as those based on SFP+. Like previous versions of Ethernet, 10GbE can use either copper or fiber cabling. Maximum distance over copp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ampere
The ampere ( , ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to 1 coulomb (C) moving past a point per second. It is named after French mathematician and physicist André-Marie Ampère (1775–1836), considered the father of electromagnetism along with Danish physicist Hans Christian Ørsted. As of the 2019 revision of the SI, the ampere is defined by fixing the elementary charge to be exactly , which means an ampere is an electric current equivalent to elementary charges moving every seconds, or approximately elementary charges moving in a second. Prior to the redefinition, the ampere was defined as the current passing through two parallel wires 1 metre apart that produces a magnetic force of newtons per metre. The earlier CGS system has two units of current, one structured similarly to the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow through semiconductors, electrical insulation, insulators, or even through a vacuum as in electron beam, electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A archaism, term formerly used for this type of current was galvanic current. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', as when they modify ''Electric current, current'' or ''voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains Electronics, electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laptop Battery
A lithium-ion or Li-ion battery is a type of rechargeable battery that uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. Li-ion batteries are characterized by higher specific energy, energy density, and energy efficiency and a longer cycle life and calendar life than other types of rechargeable batteries. Also noteworthy is a dramatic improvement in lithium-ion battery properties after their market introduction in 1991; over the following 30 years, their volumetric energy density increased threefold while their cost dropped tenfold. In late 2024 global demand passed per year, while production capacity was more than twice that. The invention and commercialization of Li-ion batteries has had a large impact on technology, as recognized by the 2019 Nobel Prize in Chemistry. Li-ion batteries have enabled portable consumer electronics, laptop computers, cellular phones, and electric cars. Li-ion batteries also see significant use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pan–tilt–zoom Camera
A pan-tilt-zoom camera (PTZ camera) is a robotic camera capable of panning horizontally (from left to right), tilting vertically (up and down), and zooming (for magnification). PTZ cameras are often positioned at guard posts where active employees may manage them using a remote camera controller. Their primary function is to monitor expansive open regions that need views in the range of 180 or 360 degrees. Depending on the camera or software being used, they may also be set up to automatically monitor motion-activated activities or adhere to a defined schedule. Functions A pan-tilt-zoom camera can be controlled remotely via computer software, or manually by a person to recognize patterns and individuals. PTZ cameras can zoom in, pan widely in all directions, and tilt up and down utilizing servomotors to change the image captured. The camera's focus triggers a corresponding motorized zoom-in on the subject of the camera's attention. In addition, the lens's versatility allows t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigabit Ethernet
In computer networking, Gigabit Ethernet (GbE or 1 GigE) is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in 1999, and has replaced Fast Ethernet in wired local networks due to its considerable speed improvement over Fast Ethernet, as well as its use of cables and equipment that are widely available, economical, and similar to previous standards. The first standard for faster 10 Gigabit Ethernet was approved in 2002. History Ethernet was the result of research conducted at Xerox PARC in the early 1970s, and later evolved into a widely implemented Physical layer, physical and Data link layer, link layer protocol. Fast Ethernet increased the speed from 10 to 100 megabits per second (). Gigabit Ethernet was the next iteration, increasing the speed to . The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Transformer
Various types of electrical transformer are made for different purposes. Despite their design differences, the various types employ the same basic principle as discovered in 1831 by Michael Faraday, and share several key functional parts. Power transformer Laminated core This is the most common type of transformer, widely used in electric power transmission and appliances to convert mains voltage to low voltage to power electronic devices. They are available in power ratings ranging from mW to MW. The insulated laminations minimize eddy current losses in the iron core. Small appliance and electronic transformers may use a split bobbin, giving a high level of insulation between the windings. The rectangular cores are made up of stampings, often in E-I shape pairs, but other shapes are sometimes used. Shields between primary and secondary may be fitted to reduce EMI (electromagnetic interference), or a screen winding is occasionally used. Small appliance and electronics t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
