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. The cable standard provides performance of up to 100 MHz and is suitable for 10BASE-T, 100BASE-TX (Fast Ethernet), and 1000BASE-T (Gigabit Ethernet). Cat 5 is also used to carry other signals such as telephony and video. In some cases, multiple signals can be carried on a single cable; Cat 5 can carry two conventional telephone lines as well as a single 100BASE-TX channel in a single cable or two 100BASE-TX channels in a single cable.
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Category 5 has been superseded by the Category 5e (enhanced) specification.[citation needed]
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 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.
Category 5 vs. 5e
The category 5e specification improves upon the category 5 specification by tightening some crosstalk specifications and introducing new crosstalk specifications that were not present in the original category 5 specification. The bandwidth of category 5 and 5e is the same - 100 MHz.[9][10]
Characteristics
Electrical characteristics for Cat 5e UTP| Property | Nominal Value | Tolerance | Unit | ref |
|---|
| Characteristic impedance @ 100 MHz | 100 | ± 15 | Ω | [11] |
| Nominal characteristic impedance @ 100 MHz | 100 | ± 5 | Ω | [11] |
| DC-Loop resistance | ≤ 0.188 | | Ω/m | [11] |
| Propagation speed | 0.64 | | c | [11] |
| Propagation delay | 4.80-5.30 | | ns/m | [11] |
| Delay skew < 100 MHz | < 0.20 | | ns/m | [11] |
| Capacitance at 800 Hz | 52 | | pF/m | [11] |
| Inductance | 525 | | nH/m | [12] |
| Corner frequency | ≤ 57 | | kHz | [12] |
| Max tensile load, during installation | 100 | | N | [11] |
| Wire diameter | AWG-24 (0.51054 mm 0.205 mm2) | | | [11][13] |
| Insulation thickness | 0.245 | | mm | [11] |
| Maximum current per conductor | 0.577 | | A | [13] |
| Temperature operating | -55 to +60 | | °C | [11] |
Maximum operating voltage
(PoE uses max 57 V DC)[14] | 125 | | V DC | [15] |
Insulation
Example materials used as insulation in the cable[16]| 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.[12][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[17][18]| Class | Phrase | Standards |
|---|
| CMP | Communications Plenum | CSA FT6[19] or NFPA 262[20] (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).
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.[17]
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.[21]
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.[22] 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.[23]
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". http://www.nag.ru/goodies/tia/TIA-EIA -568-B.1.pdf. 090917 nag.ru
- ^ As noted in ANSI/TIA/EIA-568-B-2 standard for backbone applications
- ^ "Ethernet Cable Identification and Use". Donutey. http://donutey.com/ethernet.php. Retrieved 2011-04-01.
- ^ "Selecting coax and twisted-pair cable – Electronic Products". http://www2.electronicproducts.com/Se lecting_coax_and_twisted-pair_cable-a rticle-belden-nov2005-html.aspx. 081216 www2.electronicproducts.com
- ^ "The Evolution of Copper Cabling Systems from Cat5 to Cat5e to Cat6". http://www.gocsc.com/UserFiles/File/P anduit/Panduit098765.pdf.www.panduit.com
- ^ "UTP technology by Extron Technologies". http://www.extron.com/download/files/ whitepaper/cat5-white.pdf. www.extron.com
- ^ "Cat5e Cable Wiring Schemes White Paper by B&B Electronics". http://bb-elec.com/tech_articles/NTRO N_cat5e_cable_wiring_schemes.asp. bb-elec.com
- ^ IEEE Std 802.3-2008, Institute of Electrical and Electronics Engineers, 2008, Table 13-1
- ^ UNDERSTANDING CAT - 5 CABLES, Satelliete & Cable TV, http://www.scatmag.com/technical/tech article_dec02.pdf, retrieved 2013-01-05
- ^ Cat5 Spec, cat6 specs, cat7 spec - Definitions, Comparison, Specifications, TEC Datawire, http://www.tecdatawire.com/catspec.ht ml, retrieved 2013-01-05
- ^ a b c d e f g h i j k "SuperCat OUTDOOR CAT 5e U/UTP". http://communications.draka.com/sites /eu/Datasheets/SuperCat5_24_U_UTP_Ins tall.pdf. 080319 draka.com
- ^ a b c "Transmission Line Zo". http://www.prc68.com/I/Zo.shtml. 090113 prc68.com
- ^ a b "American Wire Gauge table and AWG Electrical Current Load Limits". http://www.powerstream.com/Wire_Size. htm. 081220 powerstream.com
- ^ IEEE 802.3at-2009 Table 33-11
- ^ "Copper Data Cables". http://www.schrack.cz/fileadmin/f/cz/ INFORMACNI_TECHNOLOGIE/PIRELLI/PIRELL I__kabely_utp__ftp.pdf. 101107 schrack.cz
- ^ "UL Listed / ISO 9001 Compliant". http://unioncopper.com/. 090127 unioncopper.com
- ^ a b "CSA Flame Test Ratings". http://74.125.77.132/search?q=cache:l j1qDZvjxDAJ:www.kqtcable.com/inc.php% 3Finc%3Dinfo-CSA-Flame-Test-Ratings&a mp;hl=sv&ct=clnk&cd=2. 090126 74.125.77.132
- ^ "22Technical Information" (PDF). http://www.belden.com/pdfs/03Belden_M aster_Catalog/22Technical%2520Informa tion_Glossary/22Technical_Information .pdf.[dead link] 090126 belden.com
- ^ "CSA Flame Test Ratings". http://www.pacificcabling.com/Informa tion/flame_test_ratings.htm. Retrieved 2012-01-09.
- ^ "The Flame Tests Conducted On A Cat6 Plenum Cable". http://cat6wiring.com/cat6-plenum-cab le.php. Retrieved 2011-04-01.
- ^ "CAT5e CMR/CMX mean it's uv rated?". http://www.broadbandreports.com/forum /remark,16168746. 090126 broadbandreports.com
- ^ "A dumb mistake a green WISP operator once made.". http://www.broadbandreports.com/forum /r21017727-A-dumb-mistake-a-green-WIS P-operator-once-made. 090126 broadbandreports.com
- ^ "What are the differences between PVC, riser and plenum-rated cables?". http://sawaal.ibibo.com/computers-and -technology/oldest-answers/what-are-t he-differences-between-pvc-riser-and- plenum-rated-cables-154825.html. 090126 sawaal.ibibo.com
Unshielded and shielded twisted pair cabling standards |
|---|
| | | Categories | - Level 1
- Level 2
- Cat 3
- Cat 4
- Cat 5
- Cat 5e
- Cat 6
- Cat 6a
- Class F
|
|---|
| | - See also
- TIA/EIA-568
- Ethernet over twisted pair
- Modular connector
- Twisted pair
|
|
white/green
green
white/orange
blue
white/blue
orange
white/brown
brown
