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Networking cable
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Networking cable is a piece of networking hardware used to connect one network device to other network devices or to connect two or more computers to share devices such as printers or scanners. Different types of network cables, such as coaxial cable, optical fiber cable, and twisted pair cables, are used depending on the network's topology, protocol, and size. The devices can be separated by a few meters (e.g. via Ethernet) or nearly unlimited distances (e.g. via the interconnections of the Internet).
While wireless networks are more easily deployed when total throughput is not an issue, most permanent larger computer networks utilize cables to transfer signals from one point to another.[1]
There are several technologies used for network connections. Patch cables are used for short distances in offices and wiring closets. Electrical connections using twisted pair or coaxial cable are used within a building. Optical fiber cable is used for long distances or for applications requiring high bandwidth or electrical isolation. Many installations use structured cabling practices to improve reliability and maintainability. In some home and industrial applications, power lines are used as network cabling.
Twisted pair
[edit]
Twisted pair cabling is a form of wiring in which pairs of wires (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling out electromagnetic interference (EMI) from other wire pairs and from external sources. This type of cable is used for home and corporate Ethernet networks. Twisted pair cabling is used in short patch cables and in the longer runs in structured cabling.
There are two types of twisted pair cables: shielded and unshielded.
Ethernet crossover cable
[edit]An Ethernet crossover cable is a type of twisted pair Ethernet cable used to connect computing devices together directly that would normally be connected via a network switch, Ethernet hub or router, such as directly connecting two personal computers via their network adapters. Most current Ethernet devices support Auto MDI-X, so it does not matter whether crossover or straight cables are used.[2]
Fiber optic cable
[edit]
An optical fiber cable consists of a center glass core surrounded by several layers of protective material. The outer insulating jacket is made of Teflon or PVC to prevent interference. It is expensive but has higher bandwidth and can transmit data over longer distances.[3] There are two major types of optical fiber cables: shorter-range multi-mode fiber and long-range single-mode fiber.
Coaxial cable
[edit]
A coaxial cable forms a transmission line and confines the electromagnetic wave to an area inside the cable between the center conductor and the shield. The transmission of energy in the line occurs totally through the dielectric inside the cable between the conductors. Coaxial lines can therefore be bent and twisted (subject to limits) without negative effects, and they can be strapped to conductive supports without inducing unwanted currents in them.
Early Ethernet, 10BASE5 and 10BASE2, used baseband signaling over coaxial cables.
The most common use for coaxial cables is for television and other signals with bandwidth of multiple megahertz. Although in most homes coaxial cables have been installed for transmission of TV signals, new technologies (such as the ITU-T G.hn standard) open the possibility of using home coaxial cable for high-speed home networking applications (Ethernet over coax).
Patch cable
[edit]A patch cable is an electrical or optical cable used to connect one electronic or optical device to another for signal routing. Devices of different types (e.g., a switch connected to a computer or a switch connected to a router) are connected with patch cables. Patch cables are usually produced in many different colors so as to be easily distinguishable.[2] In contrast to structured cabling, patch cables are more flexible.
Power lines
[edit]Although power wires are not designed for networking applications, power line communication (PLC) allows these wires to also be used to interconnect home computers, peripherals or other networked consumer products. The HomePlug protocol family was an early PLC technology. In December 2008, the ITU-T adopted Recommendation G.hn/G.9960 as the first worldwide standard for high-speed powerline communications.[4] G.hn also specifies techniques for communications over the existing category 3 cable used by phones and coaxial cable used by cable television in the home.
See also
[edit]- ISO/IEC 11801, general-purpose telecommunication cabling
- Telecommunication cable
References
[edit]- ^ "Network Cables". Networktutorials.info. Archived from the original on 2010-12-24. Retrieved 2012-10-16.
- ^ a b "Ethernet Cable Identification". Donutey.com. Archived from the original on 2016-03-06.
- ^ "Data Cabling - Total Solution Computing". Retrieved 2025-12-10.
- ^ "New global standard for fully networked home" (Press release). International Telecommunication Union. 2008-12-12. Archived from the original on 2015-03-13. Retrieved 2018-02-16.
External links
[edit]
Wikimedia Commons has media related to Network cables.
- The wonderful world of wire Archived 2011-09-11 at the Wayback Machine
- Ultimate Guide to Ethernet Cables Archived 2024-09-20 at the Wayback Machine
Networking cable
View on Grokipediafrom Grokipedia
Networking cables are physical transmission media used to interconnect computers, servers, switches, and other devices in a network, enabling the reliable transfer of data signals over short to long distances.[1] These cables form the backbone of local area networks (LANs), wide area networks (WANs), and data centers, supporting various protocols like Ethernet and adhering to international standards for performance and compatibility.[2]
The primary types of networking cables include copper-based twisted-pair cables, coaxial cables, and fiber optic cables, each suited to specific speed, distance, and environmental requirements.[1] Twisted-pair cables, the most widely used for modern Ethernet networks, consist of pairs of insulated copper wires twisted together to reduce electromagnetic interference; they are categorized under the ANSI/TIA-568.2-E standard into levels such as Category 5e (supporting up to 1 Gbps over 100 meters), Category 6 (up to 10 Gbps over 55 meters), Category 6A (10 Gbps over 100 meters), and Category 8 (25/40 Gbps over 30 meters).[1][3] Unshielded twisted-pair (UTP) variants dominate due to their cost-effectiveness and ease of installation, while shielded twisted-pair (STP) offers better protection against noise in industrial settings.[1]
Coaxial cables, featuring a central copper conductor surrounded by insulation, a metallic shield, and an outer jacket, were historically prevalent in early Ethernet (e.g., 10BASE2 and 10BASE5 standards supporting 10 Mbps over 185–500 meters) but are now largely replaced by twisted-pair for LANs, retaining use in broadband internet and video applications.[1] Fiber optic cables transmit data via light pulses through glass or plastic cores, providing immunity to electromagnetic interference, higher bandwidths (up to 100 Gbps or more), and longer distances (up to kilometers); the ANSI/TIA-568.3-E standard defines categories like multimode (OM3, OM4, OM5 for short-range, high-speed LANs) and single-mode fibers such as OS1a for premises cabling and OS2 for long-haul WANs.[4] Recent advancements, such as single twisted-pair cabling in TIA-568.1-E Addendum 1 (2023), support emerging applications like Power over Ethernet (PoE) for wireless access points, requiring at least Category 6A for reliable performance.[2]
Overall, the ANSI/TIA-568 series, including the 2024 update to TIA-568.2-E for twisted-pair cabling, establishes the foundational guidelines for structured cabling systems in commercial buildings, ensuring scalability, backward compatibility, and compliance with global Ethernet standards from the IEEE 802.3 working group.[2][5] Selection of networking cables depends on factors like data rate, transmission distance, cost, and installation environment, with ongoing updates to standards addressing higher speeds (e.g., toward 1 Tbps per the 2025 Ethernet Roadmap) and energy efficiency in response to 5G backhaul integration and data center demands.[4][6]
Bandwidth in twisted pair cables is influenced by the twist length, with the maximum frequency approximately given by , where is the signal velocity in the cable (typically around 0.6–0.7 times the speed of light) and is the twist length, as shorter twists maintain pair balance at higher frequencies to reduce crosstalk.[25]
These cables are widely used for Ethernet local area networks, supporting speeds from 10 Mbps (Cat 3) to 40 Gbps (Cat 8), as well as traditional telephone lines for voice transmission.[31] Maximum channel lengths are generally 100 m for 1 Gbps over Cat 5e and 10 Gbps over Cat 6a, but reduce to 55 m for 10 Gbps over Cat 6 and 30 m for 40 Gbps over Cat 8 due to increased signal attenuation at higher frequencies.[3] They are also employed in short patch cables for device connections within equipment racks.[28]
Twisted pair cables offer advantages such as low cost, ease of installation, and compatibility with existing RJ-45 connectors, making them the standard for most LAN deployments.[29] However, they are vulnerable to EMI in noisy environments without shielding and have distance limitations compared to alternatives like coaxial cables, which provide better noise immunity for longer runs in legacy systems.[27] As of January 2025, TSB-6000 provides guidance on applications supported by these cabling systems, including protocols for speeds beyond 40 Gbps in compatible environments.[32]
Fundamentals
Definition and Classification
Networking cables serve as the physical medium for transmitting data signals between network devices in computer networks, enabling the connection of endpoints such as computers, switches, and routers. These cables typically consist of one or more conductors that carry the signal—either electrical conductors made of copper wire or optical conductors made of glass or plastic fibers—surrounded by insulation to prevent signal leakage and protect against environmental damage. Many designs also incorporate shielding, such as metallic foil or braided layers, to mitigate electromagnetic interference (EMI) by containing or blocking external noise.[7] Networking cables are primarily classified by their transmission medium into electrical types, which use copper-based conductors to carry electrical signals, and optical types, which employ fiber optics for light-based signal propagation. Electrical cables include twisted pair and coaxial variants, while optical cables encompass multimode and single-mode fibers. A further classification distinguishes signal transmission modes: balanced transmission, which uses differential signaling over two conductors to cancel out noise (as in twisted pair cables), versus unbalanced transmission, which relies on a single varying conductor relative to a grounded shield (as in coaxial cables). Twisted pair exemplifies a balanced electrical cable, while fiber optics enable high-speed, long-distance optical transmission.[7][8] Applications further categorize networking cables as short-haul, suitable for local area networks (LANs) with distances typically under 100 meters, or long-haul, designed for metropolitan or wide area networks (WANs) extending kilometers. Key characteristics influencing selection include bandwidth capacity, which determines data throughput (ranging from 10 Mb/s to 400 Gb/s or higher across types, with emerging standards up to 800 Gb/s as of 2025); attenuation rates, measuring signal loss over distance (higher in electrical cables like 10–16 dB/100 m at 10 MHz for typical Ethernet coaxial cables); maximum transmission length, limited to about 100m for many copper types but up to 40 km for single-mode fiber; susceptibility to EMI, which affects unshielded electrical cables more than optical ones; and cost factors, with copper generally cheaper for short runs but fiber offering better long-term value for high-capacity needs.[7][9][10] These cables support various network topologies, such as star configurations common in modern Ethernet setups using twisted pair for hub-based connections, and legacy bus topologies employing coaxial cable for shared linear segments. They underpin protocols like Ethernet standards, including 10BASE-T, which specifies 10 Mb/s transmission over twisted pair in a star topology with a maximum segment length of 100 meters.[7][11]Historical Evolution
The origins of networking cables trace back to the late 19th century, when foundational technologies for wired communication emerged primarily from telephony advancements. In 1881, Alexander Graham Bell patented the twisted pair cable, consisting of two insulated copper wires twisted together to reduce electromagnetic interference and crosstalk in telephone lines.[12] Similarly, in 1880, British engineer Oliver Heaviside patented the coaxial cable design, featuring a central conductor surrounded by a tubular shielding layer, which minimized signal loss over longer distances for telegraph and early electrical transmissions.[13] These inventions laid the groundwork for modern networking by enabling reliable signal transmission, though initially applied outside data networks. The 1970s and 1980s marked the Ethernet era, transforming these cables into core components of local area networks (LANs). In 1973, engineers at Xerox PARC, including Robert Metcalfe, developed 10BASE5, the first Ethernet standard using thick coaxial cable in a bus topology for 10 Mbps data rates across shared segments.[14] This was followed in the early 1980s by 10BASE2, or thin coaxial cable, which offered easier installation and lower cost for smaller networks while maintaining the bus architecture.[15] By 1990, the IEEE 802.3 standard formalized 10BASE-T, shifting to twisted pair cabling over star topologies with hubs, enabling point-to-point connections that improved scalability and fault isolation in office environments.[16] The 1990s and 2000s saw widespread adoption of fiber optic cables, addressing bandwidth limitations of copper for both LANs and wide area networks (WANs). AT&T pioneered multimode fiber in the 1970s for short-distance LAN applications, with experimental systems deployed by 1976 using graded-index fibers to support higher data rates via light pulses.[17] Single-mode fiber, developed concurrently in the early 1970s by researchers at Corning and Bell Labs, became dominant for long-haul WANs in the 1980s due to its narrower core allowing lower attenuation over distances exceeding 100 km.[18] A key milestone was the Fiber Distributed Data Interface (FDDI) standard, ratified by ANSI in the mid-1980s, which utilized dual-ring multimode fiber topologies for 100 Mbps backbone networks in enterprise settings.[19] Advancements from the 2010s onward focused on enhancing copper twisted pair for high-speed Ethernet while integrating power delivery. The TIA/EIA-568-B standard introduced Category 6 (Cat 6) cabling in 2002, supporting up to 1 Gbps over 100 meters with improved shielding against alien crosstalk. This evolved to Category 6A in 2009 for 10 Gbps capabilities, and Category 8 in 2016 under ANSI/TIA-568-C.2-1, enabling 40 Gbps over short distances in data centers with stringent shielding.[3] Concurrently, Power over Ethernet (PoE) standards emerged to transmit power alongside data; IEEE 802.3af was ratified in 2003 for up to 15.4 W per port, evolving to IEEE 802.3bt in 2018 for up to 90 W to support power-hungry devices like pan-tilt-zoom cameras.[20][21] From the 2020s, standards have continued to evolve with IEEE 802.3ck (2022) extending Ethernet to 400 Gb/s over twinaxial cables for data centers, and updates to the TIA-568-E series (as of 2024) enhancing support for higher PoE levels up to 100 W and improved cabling for emerging applications.[22][23] Networking cable evolution also involved topological shifts from shared bus configurations in early coaxial systems to star topologies with 10BASE-T, reducing collision domains and easing maintenance.[16] The rise of wireless technologies in the 1990s, such as IEEE 802.11, influenced wired cables by emphasizing complementary roles—wired for backbone reliability and high throughput where wireless latency and interference proved limiting.[24]Copper-Based Cables
Twisted Pair Cables
Twisted pair cables consist of pairs of insulated copper wires twisted around each other to minimize electromagnetic interference (EMI) through differential signaling, where induced noise voltages on both wires are approximately equal and thus cancel out during reception.[25] This construction typically involves four such pairs within a single cable jacket for data networking applications, with the twisting rate varying between pairs to further reduce crosstalk.[26] Variants of twisted pair cables include unshielded twisted pair (UTP), which relies solely on the twisting for noise rejection and is common in categories like Cat 5e and Cat 6 due to its simplicity and cost-effectiveness, and shielded variants such as shielded twisted pair (STP) or foiled twisted pair (FTP), which add metallic foil or braided shielding around the pairs or overall cable to enhance protection against external EMI in high-noise environments.[27] Additionally, conductors can be solid copper for better signal integrity and rigidity in permanent installations or stranded copper for greater flexibility in movable connections like patch cables.[28] The ANSI/TIA-568 standards, as revised in ANSI/TIA-568.2-E (2024), define requirements for balanced twisted-pair cabling in commercial buildings, specifying performance parameters such as attenuation, crosstalk, and return loss for various categories to ensure reliable structured cabling systems.[29][30] These categories include Cat 3, supporting 10 Mbps at 16 MHz, up to Cat 8, supporting up to 40 Gbps at 2000 MHz, with each higher category featuring tighter twists, improved insulation, and sometimes shielding to handle increased frequencies and data rates. (Note: Category 7 is defined under ISO/IEC 11801 standards and is not part of ANSI/TIA-568.)[31]| Category | Bandwidth (MHz) | Maximum Data Rate (Gbps) | Typical Shielding |
|---|---|---|---|
| Cat 3 | 16 | 0.01 | UTP |
| Cat 5 | 100 | 0.1 | UTP |
| Cat 5e | 100 | 1 | UTP |
| Cat 6 | 250 | 1 (10 up to 55 m) | UTP/FTP |
| Cat 6a | 500 | 10 | Enhanced UTP/FTP |
| Cat 8 | 2000 | 40 | STP/FTP |
Coaxial Cables
Coaxial cables feature a central copper conductor surrounded by a dielectric insulator, which is then enclosed by a metallic shield—typically braided or foil—and an outer protective jacket. This layered construction enables the transmission of high-frequency signals while minimizing losses and interference. Common types include RG-58, a 50-ohm cable with a solid or stranded copper center conductor, polyethylene dielectric, and tinned copper braid shield, often used in legacy networking applications, and RG-6, a 75-ohm variant with a thicker jacket and dual shielding for broadband and video distribution.[33][34][35] The characteristic impedance of a coaxial cable, denoted as , is determined by the formula , where represents the inductance per unit length and the capacitance per unit length; this value is typically standardized at 50 ohms for data networking or 75 ohms for video and RF applications to ensure efficient signal propagation without reflections.[36][37] In early Ethernet implementations, coaxial cables served as the primary medium under IEEE 802.3 standards, with 10BASE5—also known as Thicknet—using RG-8 cable to support 10 Mbps over segments up to 500 meters, connected via vampire taps and transceivers. Similarly, 10BASE2, or Thinnet, employed RG-58 cable with BNC connectors for 10 Mbps transmission across 185-meter segments, allowing simpler daisy-chaining of up to 30 nodes per segment. These configurations formed bus topologies but were limited by collision detection requirements and signal degradation over distance.[38][39][40] Today, coaxial cables remain vital for broadband internet via cable modems adhering to DOCSIS standards, which leverage hybrid fiber-coax networks to deliver high-speed data over existing 75-ohm infrastructure like RG-6. Additionally, the ITU-T G.hn standard enables Ethernet over coax, achieving up to 2 Gbps, with amendments as of 2020 supporting up to 10 Gbps over coaxial cable, by modulating signals across legacy wiring, including coaxial, for in-home or multi-dwelling unit networking. These applications also support video distribution in cable television systems, where coax carries RF signals efficiently.[41][42][43] Performance-wise, coaxial cables exhibit low attenuation at radio frequencies—typically 5-10 dB per 100 meters at 100 MHz for RG-6—allowing reliable transmission over moderate distances, though higher frequencies increase losses. The metallic shield provides superior electromagnetic interference (EMI) rejection, often exceeding 60 dB, by confining the signal within the inner layers and blocking external noise. Maximum lengths reach 500 meters in legacy Ethernet but are constrained in modern uses by signal reflections and attenuation, necessitating amplifiers or repeaters for longer runs.[44][45][46]Fiber Optic Cables
Multimode Fibers
Multimode fibers are optical fibers designed to carry multiple simultaneous light paths, or modes, making them suitable for shorter-distance, higher-bandwidth applications in local area networks (LANs). These fibers feature a relatively large core diameter, typically 50 μm or 62.5 μm for glass-based multimode, surrounded by a 125 μm cladding layer of glass with a lower refractive index to enable total internal reflection. A protective buffer coating encases the cladding to shield the fiber from environmental damage.[47][48] The core's refractive index profile distinguishes step-index from graded-index multimode fibers. In step-index fibers, the core has a uniform refractive index, leading to light rays traveling in discrete paths that arrive at the receiver at different times. Graded-index fibers, more common in modern applications, employ a parabolic refractive index gradient in the core—decreasing from the center outward—to equalize path lengths and minimize modal dispersion, the primary limitation on signal quality in multimode transmission. This design allows for higher bandwidths, with graded-index multimode fibers achieving up to 4 GHz·km in optimized configurations.[47] Light propagation in multimode fibers involves multiple modes entering the core at various angles, following different trajectories due to total internal reflection at the core-cladding boundary. The numerical aperture, determined by the refractive index difference, governs the acceptance angle of these modes. Modal dispersion arises as higher-order modes travel longer paths, causing pulse broadening; graded-index profiles mitigate this by slowing peripheral rays, preserving signal integrity over moderate distances. The bandwidth-length product quantifies this performance, with typical values such as 2000 MHz·km for OM3 at 850 nm.[47] Standards for multimode fibers are defined by ISO/IEC 11801 and TIA/EIA, categorizing them as OM1 through OM5 based on modal bandwidth and jacket color for identification. OM1 (62.5/125 μm, 200 MHz·km at 850 nm) and OM2 (50/125 μm, 500 MHz·km) use light-emitting diodes (LEDs) at 850/1300 nm wavelengths and support legacy 1 Gbps Ethernet up to 550 m. OM3 and OM4 (both 50/125 μm, aqua jacket) are laser-optimized with vertical-cavity surface-emitting lasers (VCSELs) at 850 nm, offering 2000 MHz·km and 4700 MHz·km respectively; OM3 enables 10 Gbps up to 300 m, while OM4 extends to 550 m for 10 Gbps and 150 m for 40/100 Gbps. OM5 (lime green jacket, 50/125 μm) further enhances bandwidth to 28,000 MHz·km at 850 nm and supports short-wavelength wavelength-division multiplexing (SWDM) across 850–953 nm for 40/100 Gbps up to 150 m and emerging 400 Gbps links. Common connectors include LC and SC for duplex terminations in these systems.[48][47][49] In applications, multimode fibers excel in data centers and campus networks for short-reach interconnects, supporting Ethernet standards from 10GBASE-SR to 400GBASE-SR8. For instance, OM4 facilitates 40GBASE-SR4 over 150 m using parallel optics with MPO connectors, while OM5 enables 400 Gbps in enterprise data centers with cost savings exceeding 20% compared to single-mode alternatives for reaches under 100 m. These fibers are preferred for their compatibility with VCSEL transceivers and lower deployment costs in high-density environments.[48][50] Limitations of multimode fibers stem primarily from modal dispersion, which restricts transmission distances to a maximum of 550 m for 1 Gbps on OM2, dropping to 150–550 m at 10–400 Gbps depending on the OM grade. Attenuation is higher than in single-mode fibers, typically 2.5 dB/km at 850 nm for OM3–OM5, further constraining performance over longer runs and necessitating single-mode for extended hauls.[47][48]| OM Type | Core/Cladding (μm) | Bandwidth (MHz·km at 850 nm) | Max Distance: 10 Gbps Ethernet | Jacket Color |
|---|---|---|---|---|
| OM1 | 62.5/125 | 200 | 33 m | Orange |
| OM2 | 50/125 | 500 | 82 m | Orange |
| OM3 | 50/125 | 2000 | 300 m | Aqua |
| OM4 | 50/125 | 4700 | 550 m | Aqua |
| OM5 | 50/125 | 28,000 | 550 m | Lime |