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There are various category of cable.
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In general the higher the category the more twist
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and the less susceptible the cable is to electromagnetic interference.
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The higher the category the more stringent the specification are
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for crosstalk and system noise.
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Higher cable categories typically support higher frequencies and higher speeds
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I wouldn�t try to remember all the categories of cable if I were you.
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Just see this as an explanation of the various categories
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you may encounter in networks or in documentation.
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Category 1 was previously used for telephones and modems.
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So category 1 is a grade of unshielded twisted cabling
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designed for telephone communications and was it one time the most common on
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premise wiring, this is not suitable for data transmission.
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Category 2 was previously used for telephones and data networks up to 4 Mbps.
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Category 3 was used previously for data networks up to 10 Mbps.
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It's now generally used for telephones.
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category 4 defined up to 20 MHz with speeds up to 16 Mbps.
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category 5 is defined up to 100 MHz speeds of 10 or 100 Mbps when using 2 pairs
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and 1 Gbps when using 4 pairs
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Category 1, 2 and 4 are no longer used.
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Category 3 is no longer used in data networks.
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And generally category 5 is no longer used, but there�s a lot of installations
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that have category 5, so you may still come across it.
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Cat5e was an improvement on Cat5, it supports frequencies up to 100 MHz
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and supports speed up to 1 Gbps.
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It has a maximum distance of a 100 meters
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and is similar to Cat5 but improve the Cat5 specification
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by reducing noise and signal interference
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so some crosstalk was improved with the new specification.
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The category 5 specification improves upon the category 5 specification
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by tightening some crosstalk specifications and introducing new crosstalk
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specifications that will not present in the original category 5 specification.
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The bandwidth of Cat5 and Cat5e is the same.
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In other words 100 MHz and the physical cable construction is the same
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and in reality is that most Cat5 cables meet Cat5e specification.
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Though it may not be tested or certified as such.
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Category 6 defines frequencies up to 250 MHz and increases
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the number of pair twist per inch to reduce signal noise and interference.
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It supports 10 Gbps but only up to 55 meters.
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The type of specifications in Cat6 guarantee 100 meters runs at 1 Gbps
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so category 6 cable commonly referred to us Cat6
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is the standardize cable for the gigabit Ethernet
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and is backward compatible with Cat5 or Cat5e
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and Cat3 cable standards compared to Cat5 or Cat5e
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Cat6 f1atures more stringent specifications for crosstalk and system noise.
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The cable standards provide performance up to 250 MHz
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and is suitable for 10Base-T, 100Base-TX or Fast Ethernet
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and 1000BaseT or gigabit Ethernet as well as 10 gigabit Ethernet.
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Cat6a or augmented Cat6 defined frequencies up to 500 MHz
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which is twice that of Cat6.
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It also includes improvements with regards to crosstalk
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and support speeds up to 10 Gbps
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but in this case with the extended cable length of a 100 meters.
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Cat6 maximum cable length was 55 meters
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in a favorable environment but only 37 meters in an environment
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where a lot of crosstalk to place such as when cables are bundled together.
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So cat6a or Cat6a improved the specification allowing for 10 Gbps up to 100 meters.
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Category 7 or Cat 7 defined frequencies up to 600 MHz
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and supports speeds of up to 10 Gbps up to 100 meters.
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The connectors in Cat7 can be terror connectors rather than 8P, 8C or 8 physician
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8 contact which we commonly refer to as Rj-45 connector.
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So here�s an example of a terror connector and Cat7
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notice the pairs of cable in Cat7 are protected by a foil shield
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the twisting of pairs and the number of turns per inch, is also increased
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to protect from crosstalk and in addition has a 10 copper Twinax
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category7 is also known as class F and also has a classFa
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which defined frequencies up to 100 MHz per second
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and which in theory supports speeds up to 40 Gbps and 100 Gbps at 50 meters.
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This is currently an ISO or ISO's standard
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but is not recognized by the TIA/EIA.
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For brand new installations, it�s generally recommended that Cat6a or Cat7 be use.
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If reusing existing Cat6 cabling, cable segments must be tested up to 350 MHz
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and limited by TIA/EIA recommendations.
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Now Category8 is the next generation twisted pair cabling specification
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and is being develop to support 40 Gbps
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in other words 4 times the speed of 10 Gigabit Ethernet.
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The technical recommendation for Category8 was released in March 2013
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and has both class 1 and class 2
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in other words category8.1 cable and category8.2 cables.
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Category8.1 is fully backward compatible and interoperable with category6a
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using Rj-45 connectors.
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Category8.2 is interoperable with category7 cabling
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using either Rj-45 or terror connectors.
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