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Physical layer of Ethernet IEEE 802.3
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Physical layer ofEthernet IEEE 802.3
Kassymzhomart Sagatbek
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Ethernet (/ˈiːθərnɛt/) is a family of wired computer networking technologies commonly used inlocal area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN).
It was commercially introduced in 1980 and rst standardized in 1983 as IEEE 802.3.
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Ethernet connection variants use twistedpair and ber optic links in conjunction with
switches
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Maximum distance 100 m (328 ft) over twistedpair, up to 100 km over optical ber
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International Organization for Standardization,ISO
Open Systems Interconnection model (OSI
model)
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The physical layer is the lowest layer. This layer provides mechanical,electrical and other functional aids available to enable or disable, they
maintain and transmit bits about physical connections. This may for
example be electrical signals, optical signals (optical ber, laser),
electromagnetic waves (wireless networks) or sound. The techniques
used are called technical transmission process. Devices and network
components that are associated with the physical layer, for example, the
antenna and the ampli er, plug and socket for the network cable, the
repeater, the stroke, the transceiver etc.
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Its physical layer digital bit transfer is accomplished on a wireline or cable-free transmission path. Thesharing of a transmission medium can be carried out on this layer by static multiplexing and dynamic
multiplexing. This requires not only the speci cations of certain transmission media (for example,
copper cable, ber optic cable, power grid) and the de nition of connectors further elements.
Furthermore, it must be resolved at this level, in what way a single bit to be transmitted.
This means the following: In computer networks today information is generally transmitted in the form
of bit or symbol sequences. In copper cables and radio transmission, however, are modulated high
frequency electromagnetic waves, the information carrier, in the optical waveguide light waves of a
certain wavelength or different. The information carrier know no bit strings, but can take a lot more
different states than just 0 or 1. For each type of transmission must therefore encoding are de ned.
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Fiber-optic communication is a method oftransmitting information from one place to
another by sending pulses of infrared light[1]
through an optical ber. The light is a form of
carrier wave that is modulated to carry
information. Fiber is preferred over electrical
cabling when high bandwidth, long distance, or
immunity to electromagnetic interference is
required. This type of communication can
transmit voice, video, and telemetry through
local area networks or across long distances
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An optical fiber connector joins optical fibers, and enables quicker connectionand disconnection than splicing. The connectors mechanically couple and
align the cores of fibers so light can pass. Better connectors lose very little
light due to reflection or misalignment of the fibers. In all, about 100 different
types of fiber optic connectors have been introduced to the market.[1]
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Coaxial cable, or coax (pronounced /ˈkoʊ.æks/) is a type ofelectrical cable consisting of an inner conductor surrounded by a
concentric conducting shield, with the two separated by a
dielectric (insulating material);
Coaxial cable is a type of transmission line, used to carry
high-frequency electrical signals with low losses. It is used in
such applications as telephone trunk lines, broadband internet
networking cables, high-speed computer data busses, cable
television signals, and connecting radio transmitters and
receivers to their antennas. It differs from other shielded cables
because the dimensions of the cable and connectors are
controlled to give a precise, constant conductor spacing, which is
needed for it to function ef ciently as a transmission line.
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