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Our updated Terms of Use will become effective on May 25, 2012. Find out more. Differential signaling From Wikipedia, the free encyclopedia Jump to: navigation, search This article is about electric signals via wires. For an immunological model attempting to explain how T cells survive selection during maturation, see Differential Signaling Hypothesis.

Differential signaling is a method of transmitting information electrically with two complementary signals sent on two separate wires. The technique can be used for both analog signaling, as in some audio systems, and digital signaling, as in RS-422, RS-485, Ethernet (twisted-pair only), PCI Express and USB. The opposite technique is called single-ended signaling. Elimination of noise by using differential signaling. Contents

1 Advantages 1.1 Tolerance of ground offsets 1.2 Suitability for use with low-voltage electronics 1.3 Resistance to electromagnetic interference 2 Comparison with single-ended signaling 3 Examples 4 Transmission lines 5 Use in computers 6 High-voltage differential signaling 7 See also 8 References

Advantages Tolerance of ground offsets In a system with a differential receiver, desired signals add and noise is subtracted away.

At the end of the connection, the receiving device reads the difference between the two signals. Since the receiver ignores the wires' voltages with respect to ground, small changes in ground potential between transmitter and receiver do not affect the receiver's ability to detect the signal. Suitability for use with low-voltage electronics

In the electronics industry, and particularly in portable and mobile devices, there is a continuing tendency to lower the supply voltage in order to save power and reduce unwanted emitted radiation. A low supply voltage, however, causes problems with signaling because it reduces the noise immunity. Differential signaling helps to reduce these problems because, for a given supply voltage, it gives twice the noise immunity of a single-ended system.

To see why, consider a single-ended digital system with supply voltage V_S\,. The high logic level is V_S\, and the low logic level is 0 V. The difference between the two levels is therefore V_S - 0\,\mathrm{V} = V_S. Now consider a differential system with the same supply voltage. The voltage difference in the high state, where one wire is at V_S\, and the other at 0 V, is V_S - 0\,\mathrm{V} = V_S. The voltage difference in the low state, where the voltages on the wires are exchanged, is 0\,\mathrm{V} - V_S = -V_S. The difference between high and low logic levels is therefore V_S - (-V_S) = 2V_S\,. This is twice the difference of the single-ended system. Supposing that the voltage noise on one wire is uncorrelated to the noise on the other one, the result is that it takes twice as much noise to cause an error with the differential system as with the single-ended system. In other words, the noise immunity is doubled. Resistance to electromagnetic interference

This advantage is not actually due to differential signaling itself, but to the common practice of transmitting differential signals on balanced lines.[1][2] Single-ended signals are still resistant to interference if the lines are balanced and terminated by a differential amplifier. See Balanced line for more details. Comparison with single-ended signaling

In single-ended signaling, the transmitter generates a single voltage that the receiver compares with a fixed reference voltage, both relative to a common ground connection shared by both ends.

The widely used RS-232 system is an example of single-ended signaling, which uses ±12 V to represent a signal, and anything less than ±3 V to represent the lack of a signal. The high voltage levels give the signals some immunity from noise, since few naturally occurring signals can create that sort of voltage. They also have the advantage of requiring only one wire per signal. However, they also have a serious disadvantage: they cannot run at high speeds. The effects of capacitance and inductance, which filter out high-frequency signals, limit the speed. Large voltage swings driving long cables also require significant power from the transmitting end. This problem can be reduced by using smaller voltages, but then the chance of mistaking random environmental noise for a signal becomes much more of a problem. In many instances single-ended designs are not feasible. Another difficulty is the electromagnetic interference that can be generated by a single-ended signaling system which attempts to operate at high speed. Examples

Examples of differential signaling include LVDS, differential ECL, PECL, LVPECL, current loop interfaces such as Musical Instrument Digital Interface (MIDI) hardware, RS-422, RS-485, most Ethernet physical layers, USB, Serial ATA (SATA), TMDS, FireWire?, and HDMI. LVDS is currently the only scheme that combines low power dissipation with high speed.

Examples of single-ended signaling include RS-232 and PATA. Transmission lines

The type of transmission line used to connect two devices (chips, modules) dictates the type of signaling to be used. Single-ended signaling is used with coaxial cables, in which one conductor totally screens the other from the environment. All screens (or shields) are combined into a single piece of material to form a common ground. Differential signaling is used with a balanced pair of conductors. For short cables and low frequencies, the two methods are equivalent, so cheap single-ended circuits with a common ground can be used with cheap cables. As signaling speeds become faster, wires begin to behave as transmission lines. Use in computers

Differential signaling is often used in computers to reduce electromagnetic interference, because complete screening is not possible with microstrips and chips in computers, due to geometric constraints and the fact that screening does not work at DC. If a DC power supply line and a low-voltage signal line share the same ground, the power current returning through the ground can induce a significant voltage in it. A low-resistance ground reduces this problem to some extent. A balanced pair of microstrip lines is a convenient solution, because it does not need an additional PCB layer, as a stripline does. Because each line causes a matching image current in the ground plane, which is required anyway for supplying power, the pair looks like four lines and therefore has a shorter crosstalk distance than a simple isolated pair. In fact, it behaves as well as a twisted pair. Low crosstalk is important when many lines are packed into a small space, as on a typical PCB. High-voltage differential signaling

High-voltage differential (HVD) signaling uses high-voltage signals. In computer electronics, "high voltage" normally means 5 volts or more.

SCSI-1 variations included a high voltage differential (HVD) implementation whose maximum cable length was many times that of the single-ended version. SCSI equipment for example allows a maximum total cable length of 25 meters using HVD, while single-ended SCSI allows a maximum cable length of 1.5 to 6 meters, depending on bus speed. LVD versions of SCSI allow less than 25 m cable length not because of the lower voltage, but because these SCSI standards allow much higher speeds than the older HVD SCSI.

The term high-voltage differential signaling is a generic one that describes a variety of systems. Low-voltage differential signaling or LVDS, on the other hand, is a specific system defined by a TIA/EIA standard. See also

Current mode logic (CML) Low-voltage differential signaling (LVDS) Low-voltage positive emitter-coupled logic (LVPECL) Positive emitter-coupled logic (PECL) Transition Minimized Differential Signaling (TMDS) Longitudinal voltage Differential amplifier Differential pair Twisted pair Current loop signaling

References

^ Graham Blyth. "Audio Balancing Issues". Professional Audio Learning Zone. Soundcraft. Retrieved 2009-08-25. "Let’s be clear from the start here: if the source impedance of each of these signals was not identical i.e. balanced, the method would fail completely, the matching of the differential audio signals being irrelevant, though desirable for headroom considerations." ^ "Part 3: Amplifiers". Sound system equipment (Third edition ed.). Geneva: International Electrotechnical Commission. 2000. p. 111. IEC 602689-3:2001. "Only the common-mode impedance balance of the driver, line, and receiver play a role in noise or interference rejection. This noise or interference rejection property is independent of the presence of a desired differential signal."

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Our updated Terms of Use will become effective on May 25, 2012. Find out more. Category 5 cable From Wikipedia, the free encyclopedia Jump to: navigation, search Category 5 patch cable in T568B wiring

Category 5 cable (Cat 5) is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet. It is also used to carry other signals such as telephony and video. The cable is commonly connected using punch down blocks and modular connectors. Most Category 5 cables are unshielded, relying on the twisted pair design and differential signaling for noise rejection. Category 5 has been superseded by the Category 5e (enhanced) specification. TIA/EIA-568-A.1-2001 T568A Wiring Pin Pair Wire Color 1 3 1 Pair 3 Wire 1 white/green 2 3 2 Pair 3 Wire 2 green 3 2 1 Pair 2 Wire 1 white/orange 4 1 2 Pair 1 Wire 2 blue 5 1 1 Pair 1 Wire 1 white/blue 6 2 2 Pair 2 Wire 2 orange 7 4 1 Pair 4 Wire 1 white/brown 8 4 2 Pair 4 Wire 2 brown TIA/EIA-568-B.1-2001 T568B Wiring[1] Pin Pair Wire Color 1 2 1 Pair 2 Wire 1 white/orange 2 2 2 Pair 2 Wire 2 orange 3 3 1 Pair 3 Wire 1 white/green 4 1 2 Pair 1 Wire 2 blue 5 1 1 Pair 1 Wire 1 white/blue 6 3 2 Pair 3 Wire 2 green 7 4 1 Pair 4 Wire 1 white/brown 8 4 2 Pair 4 Wire 2 brown USOC/RJ61 Wiring Pin Pair Wire Color 1 4 tip Pair 4 Wire 1 white/brown 2 3 tip Pair 3 Wire 1 white/green 3 2 tip Pair 2 Wire 1 white/orange 4 1 ring Pair 1 Wire 2 blue 5 1 tip Pair 1 Wire 1 white/blue 6 2 ring Pair 2 Wire 2 orange 7 3 ring Pair 3 Wire 2 green 8 4 ring Pair 4 Wire 2 brown Partially stripped cable showing the twisted pairs. A Cat 5e Wall outlet showing the two wiring schemes: A for T568A, B for T568B. Contents

1 Cable standard 1.1 Conductors required 1.2 Bending radius 1.3 Maximum cable segment length 2 Characteristics 2.1 Dielectric 2.2 Individual twist lengths 2.3 Environmental ratings 3 See also 4 References

Cable standard

The specification for Category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95.[citation needed] These documents specified performance characteristics and test requirements for frequencies of up to 100 MHz. Cable types, connector types and cabling topologies are defined by TIA/EIA-568-B. The cable is terminated in either the T568A scheme or the T568B scheme. The two schemes work equally well and may be mixed in an installation so long as the same scheme is used on both ends of each cable. Nearly always, 8P8C modular connectors, often referred to as RJ45, are used for connecting category 5 cable. The USOC/RJ-61 standard is used in multi-line telephone connections.

Each of the four pairs in a Cat 5 cable has differing precise number of twists per metre to minimize crosstalk between the pairs. Although cable assemblies containing 4 pairs are common, Category 5 is not limited to 4 pairs. Backbone applications involve using up to 100 pairs.[2] This use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and crosstalk from other pairs. Category 5 cabling is most commonly used for faster Ethernet networks, such as 100BASE-TX and 1000BASE-T.

The cable is available in both stranded and solid conductor forms. The stranded form is more flexible and withstands more bending without breaking and is suited for reliable connections with insulation piercing connectors, but makes unreliable connections in insulation-displacement connectors (IDCs).[clarification needed] The solid form is less expensive[citation needed] and makes reliable connections into insulation displacement connectors, but makes unreliable connections in insulation piercing connectors.[clarification needed] Taking these things into account, building wiring (for example, the wiring inside the wall that connects a wall socket to a central patch panel) is solid core, while patch cables (for example, the movable cable that plugs into the wall socket on one end and a computer on the other) are stranded. Outer insulation is typically PVC or LSOH. The specific category of cable in use can be identified by the printing on the side of the cable.[3] Conductors required

10BASE-T and 100BASE-TX Ethernet connections require two cable pairs. 1000BASE-T Ethernet connections require four cable pairs. Cat 5 and Cat 5e cables typically use 24 - 26 AWG wire. Category 6 cable tends to have slightly more copper in each cable, with standard gauges of 22 - 24 AWG.[citation needed] Bending radius

Most Category 5 cables can be bent at any radius exceeding approximately four times the diameter of the cable.[4] Maximum cable segment length

According to the ANSI/TIA/EIA standard for category 5e copper cable (TIA/EIA 568-5-A[5]), the maximum length for a cable segment is 100 meters (328 feet). If longer runs are required, the use of active hardware such as a repeater, or a switch, is necessary.[6][7] The specifications for 10BASE-T networking specify a 100 metre length between active devices.[8] This allows for 90 metres of fixed cabling, two connectors and two patch leads of 5 metres, one at each end. Characteristics Electrical characteristics for Cat 5e UTP Property Nominal Value Tolerance Unit ref Characteristic impedance @ 100 MHz 100 ± 15 Ω [9] Nominal characteristic impedance @ 100 MHz 100 ± 5 Ω [9] DC-Loop resistance ≤ 0.188 Ω/m [9] Propagation speed 0.64 c [9] Propagation delay 4.80-5.30 ns/m [9] Delay skew < 100 MHz < 0.20 ns/m [9] Capacitance at 800 Hz 52 pF/m [9] Inductance 525 nH/m [10] Corner frequency ≤ 57 kHz [10] Max tensile load, during installation 100 N [9] Wire diameter AWG-24 (0.51054 mm ) [9][11] Insulation thickness 0.245 mm [9] Maximum current per conductor 0.577 A [11] Temperature operating -55 to +60 °C [9] Dielectric Example materials used as dielectric in the cable[12] Acronym Material PVC Polyvinyl Chloride PE Polyethylene FP Foamed polyethylene FEP Teflon/fluorinated ethylene propylene FFEP Foamed Teflon/fluorinated ethylene propylene AD/PE Air dielectric/polyethylene Individual twist lengths

By altering the length of each twist, crosstalk is reduced, without affecting the characteristic impedance.[10][dubious – discuss] The distance per twist is commonly referred to as pitch. Pair color [cm] per turn Turns per [m] Green 1.53 65.2 Blue 1.54 64.8 Orange 1.78 56.2 Brown 1.94 51.7 Environmental ratings US & Canada fire certifications[13][14] Class Phrase Standards CMP Communications Plenum CSA FT6[15] or NFPA 262[16] (UL 910) CMR Communications Riser UL 1666 CMG Communications General purpose CSA FT4 CM Communications UL 1685 (UL 1581, Sec. 1160) Vertical-Tray CMX Communications Residential UL 1581, Sec. 1080 (VW-1) CMH CSA FT1

CMR (Communications Riser), insulated with high-density polyolefin and jacketed with low-smoke polyvinyl chloride (PVC) can be replaced by a CMP (Communications Plenum), insulated with fluorinated ethylene propylene (FEP) and polyethylene (PE) and jacketed with low-smoke polyvinyl chloride (PVC), due to better flame test ratings. CM (Communications) is insulated with high-density polyolefin, but not jacketed with PVC and therefore is the lowest of the three in flame resistance.[13]

Some cables are "UV-rated" or "UV-stable" meaning they can be exposed to outdoor UV radiation without significant destruction. The materials used for the mantle are usually PVC.[17]

Any cable that contains air spaces can breathe in moisture, especially if the cable runs between indoor and outdoor spaces. Warm moist air can cause condensation inside the colder parts of the cable outdoors. It may be necessary to take precautions such as sealing the ends of the cables. Some cables are suitable for "direct burial", but this usually requires that the cable be gel filled in order to hinder moisture migration into the cable.

When using a cable for a tower, attention must be given to vertical cable runs that may channel water into sensitive indoor equipment.[18] This can often be solved by adding a drip-loop at the bottom of the run of cable.

Plenum-rated cables are slower to burn and produce less smoke than cables using a mantle of materials like PVC. This also affects legal requirements for a fire sprinkler system. That is if a plenum-rated cable is used, sprinkler requirement may be eliminated.[19]

Shielded cables (FTP/STP) are useful for environments where proximity to RF equipment, may introduce electromagnetic interference, and can also be used where eavesdropping likelihood should be minimized. See also

American wire gauge (AWG) Audio over Ethernet (AoE?) Ethernet over twisted pair (10/100/1000Base-T) Power over Ethernet (PoE?)

References

^ "ANSI/TIA/EIA-568-B.1-2001 Approved: April 12, 2001 ; Commercial Building Telecommunications Cabling Standard Part 1: General Requirements". 090917 nag.ru ^ As noted in ANSI/TIA/EIA-568-B-2 standard for backbone applications ^ "Ethernet Cable Identification and Use". Donutey. Retrieved 2011-04-01. ^ "Selecting coax and twisted-pair cable - Electronic Products". 081216 www2.electronicproducts.com ^ "The Evolution of Copper Cabling Systems from Cat5 to Cat5e to Cat6".www.panduit.com ^ "UTP technology by Extron Technologies". www.extron.com ^ "Cat5e Cable Wiring Schemes White Paper by B&B Electronics". bb-elec.com ^ IEEE Std 802.3-2008, Institute of Electrical and Electronics Engineers, 2008, Table 13-1 ^ a b c d e f g h i j k "SuperCat OUTDOOR CAT 5e U/UTP". 080319 draka.com ^ a b c "Transmission Line Zo". 090113 prc68.com ^ a b "American Wire Gauge table and AWG Electrical Current Load Limits". 081220 powerstream.com ^ "UL Listed / ISO 9001 Compliant". 090127 unioncopper.com ^ a b "CSA Flame Test Ratings". 090126 74.125.77.132 ^ "22Technical Information" (PDF).[dead link] 090126 belden.com ^ "CSA Flame Test Ratings". Retrieved 2012-01-09. ^ "The Flame Tests Conducted On A Cat6 Plenum Cable". Retrieved 2011-04-01. ^ "CAT5e CMR/CMX mean it's uv rated ? - dslreports.com". 090126 broadbandreports.com ^ "A dumb mistake a green WISP operator once made. - dslreports.com". 090126 broadbandreports.com ^ "What are the differences between PVC, riser and plenum-rated cables? - Ask or Answer Questions on Computers & Technology, Ask & Read old Answers on Computers & Technology - ibibo sawaal". 090126 sawaal.ibibo.com

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Wikimedia Foundation Powered by MediaWiki? Our updated Terms of Use will become effective on May 25, 2012. Find out more. Category 5 cable From Wikipedia, the free encyclopedia Jump to: navigation, search Category 5 patch cable in T568B wiring

Category 5 cable (Cat 5) is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet. It is also used to carry other signals such as telephony and video. The cable is commonly connected using punch down blocks and modular connectors. Most Category 5 cables are unshielded, relying on the twisted pair design and differential signaling for noise rejection. Category 5 has been superseded by the Category 5e (enhanced) specification. TIA/EIA-568-A.1-2001 T568A Wiring Pin Pair Wire Color 1 3 1 Pair 3 Wire 1 white/green 2 3 2 Pair 3 Wire 2 green 3 2 1 Pair 2 Wire 1 white/orange 4 1 2 Pair 1 Wire 2 blue 5 1 1 Pair 1 Wire 1 white/blue 6 2 2 Pair 2 Wire 2 orange 7 4 1 Pair 4 Wire 1 white/brown 8 4 2 Pair 4 Wire 2 brown TIA/EIA-568-B.1-2001 T568B Wiring[1] Pin Pair Wire Color 1 2 1 Pair 2 Wire 1 white/orange 2 2 2 Pair 2 Wire 2 orange 3 3 1 Pair 3 Wire 1 white/green 4 1 2 Pair 1 Wire 2 blue 5 1 1 Pair 1 Wire 1 white/blue 6 3 2 Pair 3 Wire 2 green 7 4 1 Pair 4 Wire 1 white/brown 8 4 2 Pair 4 Wire 2 brown USOC/RJ61 Wiring Pin Pair Wire Color 1 4 tip Pair 4 Wire 1 white/brown 2 3 tip Pair 3 Wire 1 white/green 3 2 tip Pair 2 Wire 1 white/orange 4 1 ring Pair 1 Wire 2 blue 5 1 tip Pair 1 Wire 1 white/blue 6 2 ring Pair 2 Wire 2 orange 7 3 ring Pair 3 Wire 2 green 8 4 ring Pair 4 Wire 2 brown Partially stripped cable showing the twisted pairs. A Cat 5e Wall outlet showing the two wiring schemes: A for T568A, B for T568B. Contents

1 Cable standard 1.1 Conductors required 1.2 Bending radius 1.3 Maximum cable segment length 2 Characteristics 2.1 Dielectric 2.2 Individual twist lengths 2.3 Environmental ratings 3 See also 4 References

Cable standard

The specification for Category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95.[citation needed] These documents specified performance characteristics and test requirements for frequencies of up to 100 MHz. Cable types, connector types and cabling topologies are defined by TIA/EIA-568-B. The cable is terminated in either the T568A scheme or the T568B scheme. The two schemes work equally well and may be mixed in an installation so long as the same scheme is used on both ends of each cable. Nearly always, 8P8C modular connectors, often referred to as RJ45, are used for connecting category 5 cable. The USOC/RJ-61 standard is used in multi-line telephone connections.

Each of the four pairs in a Cat 5 cable has differing precise number of twists per metre to minimize crosstalk between the pairs. Although cable assemblies containing 4 pairs are common, Category 5 is not limited to 4 pairs. Backbone applications involve using up to 100 pairs.[2] This use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and crosstalk from other pairs. Category 5 cabling is most commonly used for faster Ethernet networks, such as 100BASE-TX and 1000BASE-T.

The cable is available in both stranded and solid conductor forms. The stranded form is more flexible and withstands more bending without breaking and is suited for reliable connections with insulation piercing connectors, but makes unreliable connections in insulation-displacement connectors (IDCs).[clarification needed] The solid form is less expensive[citation needed] and makes reliable connections into insulation displacement connectors, but makes unreliable connections in insulation piercing connectors.[clarification needed] Taking these things into account, building wiring (for example, the wiring inside the wall that connects a wall socket to a central patch panel) is solid core, while patch cables (for example, the movable cable that plugs into the wall socket on one end and a computer on the other) are stranded. Outer insulation is typically PVC or LSOH. The specific category of cable in use can be identified by the printing on the side of the cable.[3] Conductors required

10BASE-T and 100BASE-TX Ethernet connections require two cable pairs. 1000BASE-T Ethernet connections require four cable pairs. Cat 5 and Cat 5e cables typically use 24 - 26 AWG wire. Category 6 cable tends to have slightly more copper in each cable, with standard gauges of 22 - 24 AWG.[citation needed] Bending radius

Most Category 5 cables can be bent at any radius exceeding approximately four times the diameter of the cable.[4] Maximum cable segment length

According to the ANSI/TIA/EIA standard for category 5e copper cable (TIA/EIA 568-5-A[5]), the maximum length for a cable segment is 100 meters (328 feet). If longer runs are required, the use of active hardware such as a repeater, or a switch, is necessary.[6][7] The specifications for 10BASE-T networking specify a 100 metre length between active devices.[8] This allows for 90 metres of fixed cabling, two connectors and two patch leads of 5 metres, one at each end. Characteristics Electrical characteristics for Cat 5e UTP Property Nominal Value Tolerance Unit ref Characteristic impedance @ 100 MHz 100 ± 15 Ω [9] Nominal characteristic impedance @ 100 MHz 100 ± 5 Ω [9] DC-Loop resistance ≤ 0.188 Ω/m [9] Propagation speed 0.64 c [9] Propagation delay 4.80-5.30 ns/m [9] Delay skew < 100 MHz < 0.20 ns/m [9] Capacitance at 800 Hz 52 pF/m [9] Inductance 525 nH/m [10] Corner frequency ≤ 57 kHz [10] Max tensile load, during installation 100 N [9] Wire diameter AWG-24 (0.51054 mm ) [9][11] Insulation thickness 0.245 mm [9] Maximum current per conductor 0.577 A [11] Temperature operating -55 to +60 °C [9] Dielectric Example materials used as dielectric in the cable[12] Acronym Material PVC Polyvinyl Chloride PE Polyethylene FP Foamed polyethylene FEP Teflon/fluorinated ethylene propylene FFEP Foamed Teflon/fluorinated ethylene propylene AD/PE Air dielectric/polyethylene Individual twist lengths

By altering the length of each twist, crosstalk is reduced, without affecting the characteristic impedance.[10][dubious – discuss] The distance per twist is commonly referred to as pitch. Pair color [cm] per turn Turns per [m] Green 1.53 65.2 Blue 1.54 64.8 Orange 1.78 56.2 Brown 1.94 51.7 Environmental ratings US & Canada fire certifications[13][14] Class Phrase Standards CMP Communications Plenum CSA FT6[15] or NFPA 262[16] (UL 910) CMR Communications Riser UL 1666 CMG Communications General purpose CSA FT4 CM Communications UL 1685 (UL 1581, Sec. 1160) Vertical-Tray CMX Communications Residential UL 1581, Sec. 1080 (VW-1) CMH CSA FT1

CMR (Communications Riser), insulated with high-density polyolefin and jacketed with low-smoke polyvinyl chloride (PVC) can be replaced by a CMP (Communications Plenum), insulated with fluorinated ethylene propylene (FEP) and polyethylene (PE) and jacketed with low-smoke polyvinyl chloride (PVC), due to better flame test ratings. CM (Communications) is insulated with high-density polyolefin, but not jacketed with PVC and therefore is the lowest of the three in flame resistance.[13]

Some cables are "UV-rated" or "UV-stable" meaning they can be exposed to outdoor UV radiation without significant destruction. The materials used for the mantle are usually PVC.[17]

Any cable that contains air spaces can breathe in moisture, especially if the cable runs between indoor and outdoor spaces. Warm moist air can cause condensation inside the colder parts of the cable outdoors. It may be necessary to take precautions such as sealing the ends of the cables. Some cables are suitable for "direct burial", but this usually requires that the cable be gel filled in order to hinder moisture migration into the cable.

When using a cable for a tower, attention must be given to vertical cable runs that may channel water into sensitive indoor equipment.[18] This can often be solved by adding a drip-loop at the bottom of the run of cable.

Plenum-rated cables are slower to burn and produce less smoke than cables using a mantle of materials like PVC. This also affects legal requirements for a fire sprinkler system. That is if a plenum-rated cable is used, sprinkler requirement may be eliminated.[19]

Shielded cables (FTP/STP) are useful for environments where proximity to RF equipment, may introduce electromagnetic interference, and can also be used where eavesdropping likelihood should be minimized. See also

American wire gauge (AWG) Audio over Ethernet (AoE?) Ethernet over twisted pair (10/100/1000Base-T) Power over Ethernet (PoE?)

References

^ "ANSI/TIA/EIA-568-B.1-2001 Approved: April 12, 2001 ; Commercial Building Telecommunications Cabling Standard Part 1: General Requirements". 090917 nag.ru ^ As noted in ANSI/TIA/EIA-568-B-2 standard for backbone applications ^ "Ethernet Cable Identification and Use". Donutey. Retrieved 2011-04-01. ^ "Selecting coax and twisted-pair cable - Electronic Products". 081216 www2.electronicproducts.com ^ "The Evolution of Copper Cabling Systems from Cat5 to Cat5e to Cat6".www.panduit.com ^ "UTP technology by Extron Technologies". www.extron.com ^ "Cat5e Cable Wiring Schemes White Paper by B&B Electronics". bb-elec.com ^ IEEE Std 802.3-2008, Institute of Electrical and Electronics Engineers, 2008, Table 13-1 ^ a b c d e f g h i j k "SuperCat OUTDOOR CAT 5e U/UTP". 080319 draka.com ^ a b c "Transmission Line Zo". 090113 prc68.com ^ a b "American Wire Gauge table and AWG Electrical Current Load Limits". 081220 powerstream.com ^ "UL Listed / ISO 9001 Compliant". 090127 unioncopper.com ^ a b "CSA Flame Test Ratings". 090126 74.125.77.132 ^ "22Technical Information" (PDF).[dead link] 090126 belden.com ^ "CSA Flame Test Ratings". Retrieved 2012-01-09. ^ "The Flame Tests Conducted On A Cat6 Plenum Cable". Retrieved 2011-04-01. ^ "CAT5e CMR/CMX mean it's uv rated ? - dslreports.com". 090126 broadbandreports.com ^ "A dumb mistake a green WISP operator once made. - dslreports.com". 090126 broadbandreports.com ^ "What are the differences between PVC, riser and plenum-rated cables? - Ask or Answer Questions on Computers & Technology, Ask & Read old Answers on Computers & Technology - ibibo sawaal". 090126 sawaal.ibibo.com

[show]

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Unshielded and shielded twisted pair cabling standards [show]

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Telecommunications (general) View page ratings Rate this page What's this? Trustworthy Objective Complete Well-written I am highly knowledgeable about this topic (optional) Categories:

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This page was last modified on 10 April 2012 at 04:50. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of use for details. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. Contact us

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Wikimedia Foundation Powered by MediaWiki? Our updated Terms of Use will become effective on May 25, 2012. Find out more. Category 5 cable From Wikipedia, the free encyclopedia Jump to: navigation, search Category 5 patch cable in T568B wiring

Category 5 cable (Cat 5) is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet. It is also used to carry other signals such as telephony and video. The cable is commonly connected using punch down blocks and modular connectors. Most Category 5 cables are unshielded, relying on the twisted pair design and differential signaling for noise rejection. Category 5 has been superseded by the Category 5e (enhanced) specification. TIA/EIA-568-A.1-2001 T568A Wiring Pin Pair Wire Color 1 3 1 Pair 3 Wire 1 white/green 2 3 2 Pair 3 Wire 2 green 3 2 1 Pair 2 Wire 1 white/orange 4 1 2 Pair 1 Wire 2 blue 5 1 1 Pair 1 Wire 1 white/blue 6 2 2 Pair 2 Wire 2 orange 7 4 1 Pair 4 Wire 1 white/brown 8 4 2 Pair 4 Wire 2 brown TIA/EIA-568-B.1-2001 T568B Wiring[1] Pin Pair Wire Color 1 2 1 Pair 2 Wire 1 white/orange 2 2 2 Pair 2 Wire 2 orange 3 3 1 Pair 3 Wire 1 white/green 4 1 2 Pair 1 Wire 2 blue 5 1 1 Pair 1 Wire 1 white/blue 6 3 2 Pair 3 Wire 2 green 7 4 1 Pair 4 Wire 1 white/brown 8 4 2 Pair 4 Wire 2 brown USOC/RJ61 Wiring Pin Pair Wire Color 1 4 tip Pair 4 Wire 1 white/brown 2 3 tip Pair 3 Wire 1 white/green 3 2 tip Pair 2 Wire 1 white/orange 4 1 ring Pair 1 Wire 2 blue 5 1 tip Pair 1 Wire 1 white/blue 6 2 ring Pair 2 Wire 2 orange 7 3 ring Pair 3 Wire 2 green 8 4 ring Pair 4 Wire 2 brown Partially stripped cable showing the twisted pairs. A Cat 5e Wall outlet showing the two wiring schemes: A for T568A, B for T568B. Contents

1 Cable standard 1.1 Conductors required 1.2 Bending radius 1.3 Maximum cable segment length 2 Characteristics 2.1 Dielectric 2.2 Individual twist lengths 2.3 Environmental ratings 3 See also 4 References

Cable standard

The specification for Category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95.[citation needed] These documents specified performance characteristics and test requirements for frequencies of up to 100 MHz. Cable types, connector types and cabling topologies are defined by TIA/EIA-568-B. The cable is terminated in either the T568A scheme or the T568B scheme. The two schemes work equally well and may be mixed in an installation so long as the same scheme is used on both ends of each cable. Nearly always, 8P8C modular connectors, often referred to as RJ45, are used for connecting category 5 cable. The USOC/RJ-61 standard is used in multi-line telephone connections.

Each of the four pairs in a Cat 5 cable has differing precise number of twists per metre to minimize crosstalk between the pairs. Although cable assemblies containing 4 pairs are common, Category 5 is not limited to 4 pairs. Backbone applications involve using up to 100 pairs.[2] This use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and crosstalk from other pairs. Category 5 cabling is most commonly used for faster Ethernet networks, such as 100BASE-TX and 1000BASE-T.

The cable is available in both stranded and solid conductor forms. The stranded form is more flexible and withstands more bending without breaking and is suited for reliable connections with insulation piercing connectors, but makes unreliable connections in insulation-displacement connectors (IDCs).[clarification needed] The solid form is less expensive[citation needed] and makes reliable connections into insulation displacement connectors, but makes unreliable connections in insulation piercing connectors.[clarification needed] Taking these things into account, building wiring (for example, the wiring inside the wall that connects a wall socket to a central patch panel) is solid core, while patch cables (for example, the movable cable that plugs into the wall socket on one end and a computer on the other) are stranded. Outer insulation is typically PVC or LSOH. The specific category of cable in use can be identified by the printing on the side of the cable.[3] Conductors required

10BASE-T and 100BASE-TX Ethernet connections require two cable pairs. 1000BASE-T Ethernet connections require four cable pairs. Cat 5 and Cat 5e cables typically use 24 - 26 AWG wire. Category 6 cable tends to have slightly more copper in each cable, with standard gauges of 22 - 24 AWG.[citation needed] Bending radius

Most Category 5 cables can be bent at any radius exceeding approximately four times the diameter of the cable.[4] Maximum cable segment length

According to the ANSI/TIA/EIA standard for category 5e copper cable (TIA/EIA 568-5-A[5]), the maximum length for a cable segment is 100 meters (328 feet). If longer runs are required, the use of active hardware such as a repeater, or a switch, is necessary.[6][7] The specifications for 10BASE-T networking specify a 100 metre length between active devices.[8] This allows for 90 metres of fixed cabling, two connectors and two patch leads of 5 metres, one at each end. Characteristics Electrical characteristics for Cat 5e UTP Property Nominal Value Tolerance Unit ref Characteristic impedance @ 100 MHz 100 ± 15 Ω [9] Nominal characteristic impedance @ 100 MHz 100 ± 5 Ω [9] DC-Loop resistance ≤ 0.188 Ω/m [9] Propagation speed 0.64 c [9] Propagation delay 4.80-5.30 ns/m [9] Delay skew < 100 MHz < 0.20 ns/m [9] Capacitance at 800 Hz 52 pF/m [9] Inductance 525 nH/m [10] Corner frequency ≤ 57 kHz [10] Max tensile load, during installation 100 N [9] Wire diameter AWG-24 (0.51054 mm ) [9][11] Insulation thickness 0.245 mm [9] Maximum current per conductor 0.577 A [11] Temperature operating -55 to +60 °C [9] Dielectric Example materials used as dielectric in the cable[12] Acronym Material PVC Polyvinyl Chloride PE Polyethylene FP Foamed polyethylene FEP Teflon/fluorinated ethylene propylene FFEP Foamed Teflon/fluorinated ethylene propylene AD/PE Air dielectric/polyethylene Individual twist lengths

By altering the length of each twist, crosstalk is reduced, without affecting the characteristic impedance.[10][dubious – discuss] The distance per twist is commonly referred to as pitch. Pair color [cm] per turn Turns per [m] Green 1.53 65.2 Blue 1.54 64.8 Orange 1.78 56.2 Brown 1.94 51.7 Environmental ratings US & Canada fire certifications[13][14] Class Phrase Standards CMP Communications Plenum CSA FT6[15] or NFPA 262[16] (UL 910) CMR Communications Riser UL 1666 CMG Communications General purpose CSA FT4 CM Communications UL 1685 (UL 1581, Sec. 1160) Vertical-Tray CMX Communications Residential UL 1581, Sec. 1080 (VW-1) CMH CSA FT1

CMR (Communications Riser), insulated with high-density polyolefin and jacketed with low-smoke polyvinyl chloride (PVC) can be replaced by a CMP (Communications Plenum), insulated with fluorinated ethylene propylene (FEP) and polyethylene (PE) and jacketed with low-smoke polyvinyl chloride (PVC), due to better flame test ratings. CM (Communications) is insulated with high-density polyolefin, but not jacketed with PVC and therefore is the lowest of the three in flame resistance.[13]

Some cables are "UV-rated" or "UV-stable" meaning they can be exposed to outdoor UV radiation without significant destruction. The materials used for the mantle are usually PVC.[17]

Any cable that contains air spaces can breathe in moisture, especially if the cable runs between indoor and outdoor spaces. Warm moist air can cause condensation inside the colder parts of the cable outdoors. It may be necessary to take precautions such as sealing the ends of the cables. Some cables are suitable for "direct burial", but this usually requires that the cable be gel filled in order to hinder moisture migration into the cable.

When using a cable for a tower, attention must be given to vertical cable runs that may channel water into sensitive indoor equipment.[18] This can often be solved by adding a drip-loop at the bottom of the run of cable.

Plenum-rated cables are slower to burn and produce less smoke than cables using a mantle of materials like PVC. This also affects legal requirements for a fire sprinkler system. That is if a plenum-rated cable is used, sprinkler requirement may be eliminated.[19]

Shielded cables (FTP/STP) are useful for environments where proximity to RF equipment, may introduce electromagnetic interference, and can also be used where eavesdropping likelihood should be minimized. See also

American wire gauge (AWG) Audio over Ethernet (AoE?) Ethernet over twisted pair (10/100/1000Base-T) Power over Ethernet (PoE?)

References

^ "ANSI/TIA/EIA-568-B.1-2001 Approved: April 12, 2001 ; Commercial Building Telecommunications Cabling Standard Part 1: General Requirements". 090917 nag.ru ^ As noted in ANSI/TIA/EIA-568-B-2 standard for backbone applications ^ "Ethernet Cable Identification and Use". Donutey. Retrieved 2011-04-01. ^ "Selecting coax and twisted-pair cable - Electronic Products". 081216 www2.electronicproducts.com ^ "The Evolution of Copper Cabling Systems from Cat5 to Cat5e to Cat6".www.panduit.com ^ "UTP technology by Extron Technologies". www.extron.com ^ "Cat5e Cable Wiring Schemes White Paper by B&B Electronics". bb-elec.com ^ IEEE Std 802.3-2008, Institute of Electrical and Electronics Engineers, 2008, Table 13-1 ^ a b c d e f g h i j k "SuperCat OUTDOOR CAT 5e U/UTP". 080319 draka.com ^ a b c "Transmission Line Zo". 090113 prc68.com ^ a b "American Wire Gauge table and AWG Electrical Current Load Limits". 081220 powerstream.com ^ "UL Listed / ISO 9001 Compliant". 090127 unioncopper.com ^ a b "CSA Flame Test Ratings". 090126 74.125.77.132 ^ "22Technical Information" (PDF).[dead link] 090126 belden.com ^ "CSA Flame Test Ratings". Retrieved 2012-01-09. ^ "The Flame Tests Conducted On A Cat6 Plenum Cable". Retrieved 2011-04-01. ^ "CAT5e CMR/CMX mean it's uv rated ? - dslreports.com". 090126 broadbandreports.com ^ "A dumb mistake a green WISP operator once made. - dslreports.com". 090126 broadbandreports.com ^ "What are the differences between PVC, riser and plenum-rated cables? - Ask or Answer Questions on Computers & Technology, Ask & Read old Answers on Computers & Technology - ibibo sawaal". 090126 sawaal.ibibo.com

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