Category 2 cable, also known as Cat 2, is a grade of unshielded twisted pair cabling designed for telephone and data communications. The maximum frequency suitable for transmission over Cat 2 cable is 4 MHz, and the maximum bandwidth is 4 Mbit/s.[1] Cat 2 cable contains 4 pairs of wires, or 8 wires total.[2]
Official TIA/EIA-568 standards have only been established for cables of Category 3 ratings or above. Though not an official category standard established by TIA/EIA, Category 2 has become the de facto name given to Level 2 cables originally defined by Anixter International, the distributor.[citation needed]
Anixter Level 2 cable was frequently used on ARCnet and 4 Mbit/s token ring networks, it is also used in telephone networks but it is no longer commonly used.
References[edit]Citations and notes[edit]Bibliography[edit]
External links[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Category_2_cable&oldid=797158954'
Cat-5 cable, sometimes called Ethernet cable, is short for Category 5 cable, a current industry standard for network and telephone wiring. This type of cable is unshielded wire containing four pairs of 24-gauge twisted copper pairs, terminating in an RJ-45 jack. If a wire is certified as Cat-5 and not just a twisted pair wire, it will have this designation printed on the outside.
The outer sheath of this type of cable can come in many colors, with bright blue being quite common. Inside, the twisted pairs are also sheathed in plastic with a standard color scheme: solid orange, blue, green and brown wires twisted around mates that are white and striped with a solid color. The twisted pairs reduce interference and crosstalk, and they should be left twisted except at the termination point. Some experts recommend untwisting only 0.5 inch (12.7 mm) of the pairs to strip and make connections. Cat-5 cable can be purchased off a spool in varying lengths, or bought pre-cut to standard lengths with RJ-45 jacks already attached.
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Cat5 ethernet cables use only 2 pairs for Ethernet what are the other 2 pairs for ?
wazoox
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marked as duplicate by Iain, Dennis Kaarsemaker, kasperd, Community♦Dec 29 '16 at 11:05
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First, keep in mind that cat5 type of cables were designed for many uses, not only for 'ethernet over twisted pair', although it's the most popular application of those cables nowadays. As you can read on Wikipedia page about 'Category 5 cable' in 'Applications' section:
Cat 5 is also used to carry other signals such as telephony and video
But let's get back to ethernet. If you will use gigabit connection, then all 4 pairs will be used, as you can see in this article How Gigabit Ethernet Works. With fast ethernet connections only 2 pairs are being used, as you mentioned. Insidious chapter 3 full movie in hindi kickass.
So one reason to put 4 pairs in cat5 cables is that they may wanted to future proof for gigabit ethernet, so introducing in the future something better than fast ethernet will not require you to change cables, and therefore the transistion to next generation ethernet will be easier.
The additional pairs in fast ethernet networks may also be used for PoE (Power over Ethernet), as you can read here:
Power over Ethernet or PoE describes any of several standardized or ad-hoc systems which pass electric power along with data on twisted pair Ethernet cabling. This allows a single cable to provide both data connection and electric power to devices such as wireless access points and IP cameras. wikipedia
That said, sometimes people who run small fast ethernet networks are using additional pairs to use them as 'second cable'. You just need to split cable into two on both ends (two pairs with ethernet connector, and other two pairs with other ethernet connector), and you have two fast ethernet connections using one cat 5 cable. You could actually buy a device like 'cat 5 cable splitter', that will allow you to do that easily. Because sometimes it's easier to split cable, than to introduce second cable when first one is for example well hidden in the floor, or wall.
It makes sense, since you could also read on wikipedia about 'Category 5 cable' in 'Shared cable' section, that:
In some cases, multiple signals can be carried on a single cable
//EDIT: I found that similar question has been asked in the past on serverfault, and you could find interesting answers there to: Why do ethernet cables have 8 wires?
People are claiming there that additional pairs may also work as additional shielding. Also someone posted there example of 'shared cable' use, by mentioning that you could route telephone signal in regular cable and it will work without a splitter
Community♦
LearnerLearner
Not the answer you're looking for? Browse other questions tagged ethernetcablecat or ask your own question.
This question already has an answer here:
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Cat5 ethernet cables use only 2 pairs for Ethernet what are the other 2 pairs for ?
wazoox
4,99144 gold badges2424 silver badges4949 bronze badges
Ravi Teja BonamRavi Teja Bonam
marked as duplicate by Iain, Dennis Kaarsemaker, kasperd, Community♦Dec 29 '16 at 11:05
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
1 Answer
First, keep in mind that cat5 type of cables were designed for many uses, not only for 'ethernet over twisted pair', although it's the most popular application of those cables nowadays. As you can read on Wikipedia page about 'Category 5 cable' in 'Applications' section:
Cat 5 is also used to carry other signals such as telephony and video
But let's get back to ethernet. If you will use gigabit connection, then all 4 pairs will be used, as you can see in this article How Gigabit Ethernet Works. Attack on titan tribute game mods. With fast ethernet connections only 2 pairs are being used, as you mentioned.
So one reason to put 4 pairs in cat5 cables is that they may wanted to future proof for gigabit ethernet, so introducing in the future something better than fast ethernet will not require you to change cables, and therefore the transistion to next generation ethernet will be easier.
The additional pairs in fast ethernet networks may also be used for PoE (Power over Ethernet), as you can read here:
Power over Ethernet or PoE describes any of several standardized or ad-hoc systems which pass electric power along with data on twisted pair Ethernet cabling. This allows a single cable to provide both data connection and electric power to devices such as wireless access points and IP cameras. wikipedia
That said, sometimes people who run small fast ethernet networks are using additional pairs to use them as 'second cable'. You just need to split cable into two on both ends (two pairs with ethernet connector, and other two pairs with other ethernet connector), and you have two fast ethernet connections using one cat 5 cable. You could actually buy a device like 'cat 5 cable splitter', that will allow you to do that easily. Because sometimes it's easier to split cable, than to introduce second cable when first one is for example well hidden in the floor, or wall.
It makes sense, since you could also read on wikipedia about 'Category 5 cable' in 'Shared cable' section, that:
In some cases, multiple signals can be carried on a single cable
//EDIT: I found that similar question has been asked in the past on serverfault, and you could find interesting answers there to: Why do ethernet cables have 8 wires?
People are claiming there that additional pairs may also work as additional shielding. Also someone posted there example of 'shared cable' use, by mentioning that you could route telephone signal in regular cable and it will work without a splitter
Community♦
Cat 5 Cable Wiring Diagram
LearnerLearner
Not the answer you're looking for? Browse other questions tagged ethernetcablecat or ask your own question.2 Pair Cat 5 Cable
hi
i have lots of noise on my DSL line and im going to change the cables i live in the 3rd floor of an apartment and the problem is the cable that comes from the main box to my apartment i think its about 30 or 40 meters its 17 years old and very close to power lines so based on what i saw on the internet i need cat 5 cable with shields in it (idk if cat5's have shields or not) , i found a company that provides those near me and what they have is cat 6 not 5 but it does have shields its called cca-sftp-cat6 and this the picture they have of it https://v14i.imgup.net/cat6-sftp05382.png https://g18i.imgup.net/cat6-sftp03389.jpg it has braided aluminium shield and they say it supports power over ethernet they also say its compatible with tyco and AMP connectors idk what those are for , but thought it may help the main cable that comes in the building is a 2 pair solid copper cable like this http://www.communica.co.za/Content/Catalog/Images/I3096504107.jpg so are all cat 6 cables 4 pair cables? can i find something with similar shields and just 1 pair? Comments are closed.
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