Twisted pair cable marking. What is twisted pair, where and how is it used? Double Shielded STP Cable
Interesting fact: The first transatlantic telephone cable was laid in 1858. from Valencia Bay (Ireland) to Newfoundland Island (off the coast of Canada). Before this, the telegraph cable was already widely used both on land and at sea: in particular, it connected France and England across the English Channel. The mass of the transatlantic cable was so great that it was carried simultaneously by two ships. The ships reached the middle of the Atlantic Ocean, where they went in different directions and a few months later the first transatlantic cable was successfully laid. An incredible euphoria arose on both sides of the ocean; many wanted to immediately send a telegram overseas for any money. But due to miscalculations in the cable insulation, only the first short telegrams were transmitted. It took several more years and several failures until a properly functioning cable was laid in 1866.
1. Definition of "twisted pair"
Words twisted pair- this is a literal translation from in English term telephone cable. In a telephone cable, the cores are twisted/twisted in pairs, because This design reduces electromagnetic interference from external and mutual interference. In the Soviet Union, pairwise twists of current-carrying cores were used, in particular, in crossover wire (PKSV brand) and in the more widely known telephone cable of the TPP brand (corresponding to the 3rd category of twisted pair). By the way, the TPP cable is still the main component in telephone networks CIS countries. In Ukraine, a faster and more reliable fiber optic telephone cable so far connects only regional centers and certain particularly important facilities.
Since the main purpose of twisted pair cable is telephone lines, - then the number of pairs in a twisted pair can be up to 1000, and the diameter of the cores is from 0.4 to 0.64 mm. Those. everything is the same as with our TPP cable. The American classification of telephone cable by category over time has proven to be the most convenient, and most factories in the world are increasingly using American terms and standards when producing telephone cable. This, for example, explains why the standard coil length of twisted pair cable is 305 m, which corresponds to 1000 feet.
With the advent of fiber optics, copper telephone cables stranded in pairs throughout the world are becoming a thing of the past. At the same time, already in our generation we see how the term twisted pair (telephone cable) has actually transformed exclusively into a 4-pair cable for computer networks.
2. Categories of twisted pair
Concept twisted pair category It is connected, first of all, with the speed of information transfer. Neither the internal design of the cable, nor the materials, etc. do not directly determine the cable category. Materials and design must provide the necessary technical characteristics: speed, durability, maximum transmission distance, etc. Today, seven categories of twisted pair cables are standardized in the world. Category 5 cable currently takes up the largest volume when laying new networks.
The speed of signal transmission directly depends on the frequency of current oscillations. Each oscillation is the transmission of some signal/value. Thus, the higher the frequency, the higher the speed. That is why the cable category standards indicate the frequency range in which this cable can work. Other factors: for example, the class of equipment or the quality of cable networks, can only maintain a given frequency/speed, and in the worst case will create interference.
| Twisted pair cable categories, characteristics. | |
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CAT1 - frequency band 0.1 MHz. In the USSR, the technical name for TRP is “noodles”. It is still used today when laying wires from the panel to the apartment. |
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CAT2 - 1 MHz frequency band (transmission speed approximately 4 Mbit/s). It is still used today to connect telephone sets to a telephone box. |
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CAT3 - 16 MHz frequency band (transmission speed 10 Mbit/s or 100 Mbit/s at a distance of no further than 100 m) |
| CAT4 frequency band 20 MHz (16 Mbit/s). Not used. | |
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CAT5 (earlier modification - CAT5e) - frequency band 100 MHz (100 Mbit/s). 125 MHz (100 Mbps when using 2 pairs and up to 1000 Mbps when using 4 pairs). The cable of this category is the most widely used. |
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CAT6 frequency band 250 MHz (1000 Mbit/s which corresponds to 1 Gbit/s) |
| CAT6a frequency band 500 MHz (10 Gbit/s). Added to the standard in February 2008. | |
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CAT7 frequency band 600-700 MHz (10 Gbit/s) is so far approved only by the international standard ISO 11801 |
For reference: one signal (dot or dash) in computer science is called one bit. Each electrical signal (pulse) means a dot/dash in a telegraph or a zero/one in binary system computer. A set of several bits forms some semantic value (letter, number, etc.) and is called a byte. Modern computer programs More often they use a 16-bit system: each set of 16 bits corresponds to one specific value. Obviously, the more bits in one byte, the more combinations semantic meanings can be formed in such a standard. Computers with 32-bit data encoding systems are already in use, and a 62-bit encoding system is being developed. In many “simple” cases, the old 6,8 and 9-bit standards are still used.
3.Types of twisted pair: purpose and marking
- Today there are the following brands of twisted pair:
U/UTP - unshielded cable (formerly “UTP”)
F/UTP - cable with a common shield for all pairs (formerly “FTP”)
SF/UTP cable with common double screen aluminum foil core + tinned copper wire “braids” (formerly “S-FTP”)
U/FTP – cable with a separate shield for each pair (formerly “STP”)
F/FTP – cable with a separate shield for each pair, as well as a common shield for all pairs made of aluminum “foil”
S/FTP - cable with a separate shield for each pair, as well as a common shield for all pairs of tinned copper wires (formerly “S-STP”)
As you can see, the main difference is the presence and type of screen. The twisted pair shield serves to protect the signal from external interference. For example, when it is not possible to lay twisted pair cables separately from power cables.
PVC - PVC plastic compound. For internal use
PP - polypropylene. For external laying mainly for high temperatures- up to +140°С,
PE - polyethylene. For external gasket
FR - fire resistant. Can work in open flame specified time: today fire-resistant shells have been standardized for 30, 90 and 180 minutes.
LS - Low Smoke reduced smoke emission during combustion
ZH - Zero Halogen is made from materials that do not emit toxic halogen gases when burned
B - Reservation. Most often, steel tape is used for armor, which is wrapped along the cable.
With a cable. The cable is needed to tension the cable between buildings.
In addition, each manufacturer may add other designations depending on the cable design, for example:
Solid or stranded core(English patch). The most widespread, as it is cheaper, was the multiplier. Stranded core is used in installation areas where frequent cable bends are possible, as well as for the manufacture of patch cords. A patch cord is a piece of cable of a certain length with jacks at the ends for connecting two digital devices.
Core diameter. From 0.4 to 0.64 mm. According to the standard, in the 5th and 6th categories, conductors with a diameter of at least 0.51 mm or 24AWG according to American marking are used. Not certified cable may have cores with a diameter of 0.4 to 0.5 mm, which is usually sufficient for connecting home Internet.
Number of pairs As mentioned earlier, the number of pairs can be up to 1000. For computer systems a 4-pair cable is used (denoted as 4x2x0.51). All four pairs are used only when creating networks with speeds up to 1 Gbit/s. In most cases: small office networks, connection home internet and other networks with speeds up to 100 Mbit/s - only two pairs are used. For such networks, as well as for alarm devices and intercoms, a 2-pair twisted pair is produced: marked accordingly 2x2x0.51.
Shell. In this matter, twisted pair cable everything is the same as with other types of cables: outer shell depends on the conditions of cable installation and operation. The most common types of shells you can find are:
Thus, the marking U/UTP 4 cat5e solid 24AWG LSZH translates as follows: unshielded cable, contains 4 pairs of 2 cores, category 5, solid - single-wire core, 24 AWG - diameter 0.51 mm, LSZH - halogen-free cable with low smoke emission .
4.Standards and certification.
In the field of twisted pair, standards can be divided into two types: The first type is Ethernet standards, which determine information transmission speeds, signal modulation methods, transmission distances, etc. In most standards Ethernet twisted steam is used as a means of signal transmission. However, there are Ethernet standards, where it is possible, and sometimes necessary, to use other cabling systems: for example, based on optical fiber.
The second type of standards are standards based on structured cable networks. They describe cable laying conditions, types of connections, etc.
Thus, when designing a cable, a twisted pair manufacturer must decide: for which Ethernet type will this twisted pair be produced and in which cable systems it will be possible to install it. Or even more clearly: what types of equipment can be connected using this cable and with what standard connectors.
There are already several dozen Ethernet standards today: from the old 10BASE5, IEEE 802.3 (also called “thick Ethernet”) to gigabit Ethernet (1000BASE). 40 standards have been developed and are already being applied Gigabit Ethernet and 100 Gigabit Ethernet. Experts are confident that a terabit one should appear in the near future!!! Internet.
In the field of SCS there are currently 3 main standards:
"EIA/TIA-568С Commercial Building Telecommunications Wiring Standard - American standard;
"ISO/IEC IS 11801-2002 Information Technology. Generic cabling for customer premises - international standard;
"CENELEC EN 50173 Information Technology. Generic cabling systems - European standard.
The technical level specified by the current standards guarantees the operability of the cable system for at least 10 years.
5.How to determine the quality of twisted pair cables in the field.
Firstly, by brand name. In Ukraine, among branded cables you can most often find twisted pair cables from the American concern Mollex or the Swiss company Reichle De-Massari AG. We have not encountered any counterfeits yet, apparently because these cables are very expensive, experts know them well, and the customers for such cables are very serious. Also, twisted pair cable from the Odeskabel plant can be considered branded in the post-Soviet space. Other trade marks, present on our market, are produced mainly in China (sometimes in Taiwan), and are labeled at the request of various customers.
Secondly, according to the material lived. As a standard, the conductors should be copper, but in Lately so-called bimetallic conductors have become widespread, which are copper-plated, or more correctly clad, i.e. thin copper-clad steel conductor (CCS = Copper Clad Steel) or copper-clad aluminum conductor (CCA = Copper Clad Aluminium). In both cases, the use of cheaper materials significantly worsens the cable characteristics, namely:
The core does not hold well in the connector (floating contact)
short segment length: usually up to 25m
unpredictability of wave resistance in the contact zone when embedding the cable into the connector
unpredictable change in characteristics during subsequent cable relaying
for copper-plated steel cables, the speed often does not exceed 10 Mbit/s, for aluminum-copper cables - no more than 100 Mbit/s.
It’s easy to check a copper-plated cable: you need to scrape off the top layer of copper with any knife. If you see a clearly white color, this is the so-called “copper deposit.” And one more thing - a copper-plated cable cannot be soldered, at least with a standard soldering iron. Unfortunately, the majority of Kyiv (as, probably, the majority of Ukrainian) Internet service operators lay exclusively copper-plated twisted pair cable from the panel to the subscriber.
Recently, a cable made of an alloy of copper with various metals has appeared. The alloy is very similar in appearance and characteristics to copper but, of course, cheaper. Unfortunately, we don’t know anything more yet, except that some operators certify such a cable here in Ukraine.
Third, according to the thickness of the veins. Serious manufacturers use a copper core with a diameter of 0.51 mm and above. Non-branded brands can have a core diameter from 0.4 to 0.51 mm. As a rule, the veins on the blue (4-5) and brown (7-8) pairs are most strongly underestimated, because Most computer networks do not use these pairs.
Fourthly, upon availability of a certificate. Ukraine does not oblige the certification of twisted pair cables, but reputable manufacturers undergo certification in our country voluntarily.
6.What you need to know when installing twisted pair cables in your apartment or house.
When laying twisted pair cables in an apartment or private house, it is completely unnecessary to take a “cool” cable of the 6th or even 7th category. Firstly, neither active nor passive equipment has yet been produced under the seventh category, and this cable is laid with a view to the future. Secondly, Internet providers do not yet provide the speed that category 6 or 7 twisted pair cables can provide. And thirdly, a category 5 cable can provide speeds of up to 100 Mbit/s, while 4 Mbit/s is sufficient for watching videos or online games.
A twisted pair cable should last at least fifteen years, so it is advisable to install copper cable in the walls. If the apartment is not yours, then a copper-plated cable will be enough: for two or three years.
The signal quality via cable is always higher than the radio signal. If you want to have high speed now and in the future, clearly plan the cable outlet locations for the Internet connection.
It is better to leave 2-3 meters of cable where the twisted pair cable is connected to the computer, but do not install a socket! Any additional twisted pair connection “steals” speed.
A twisted pair cable cannot be mechanically branched into 2-3 computers, as, for example, telephone socket. To connect two or more computers to one cable, you need a switch, more often called a switch. Standard switches are available in 2,4,6,8,12, 24, etc. subscribers.
For creating wireless networks used WI-FI technology. To do this, you must connect to your Internet provider via special device: a router (router) that connects to the Internet and transmits radio signals to your computers. Computers, in turn, must have a WI-FI unit: built-in or external. It must be remembered that after the third wall the signal from the router may weaken significantly. Although it also happens that the signal passes through two apartments, it remains quite strong. Unfortunately, it is very difficult to determine the signal range in advance; you need to try it on the spot.
The minimum permissible distance between power (electrical) and telephone cables must be at least 5 cm. In practice, this standard is violated everywhere, which in most cases does not lead to a noticeable deterioration in signal quality for the consumer.
Be very careful when using twisted pair cables in the screen. Shielded twisted pair is certainly more reliable than unshielded, but this is only if the shield is grounded. An ungrounded screen can produce additional interference - interference. In addition, the shield grounding in twisted pair must be done from one of the “terminators”, but not from both sides at once and not somewhere in the middle - this can lead to a complete loss of communication. Also be aware that some devices, such as repeaters, automatically ground the end of the cable connected to them.
And good luck to you in your endeavors
Last changes made 06/15/17
Twisted pair is a type of communication cable, which is presented in the form of a pair of conductors covered with insulation and twisted together with a certain pitch. Double conductors are combined into multi-pair wires, which are covered with a common protective sheath.
Depending on the pitch of twisting of pairs, the number of double cores, the material of the outer covering, the type of insulation and shielding, the area of use of the wire is determined. Such wires are part of a structured cabling system, and therefore are widely used in telecommunications, video surveillance, and computer networks.
To build a local home or office network FTP cable 5e is most often used. If you decide to create your own local computer network in your apartment or for other reasons you need a twisted pair cable, then it’s worth figuring out what type you need to purchase.
Twisted pair shielding type
Shielding is the protection of conductors (or cores) from electromagnetic radiation that can affect transmitted data and speed.
There are several types of cable, depending on how the cores inside are shielded.
Unshielded UTP Wire
The cheapest type, limited in its use due to instability to crosstalk and EMI. Represents one or more pairs united by an outer shell.
Shielded FTP cable
It is more protected from EMR in that it has a common shield that covers all the wires with foil. It is the most popular type of cable and is used almost everywhere. It is slightly more expensive than UTP, but it ensures the integrity of the transmitted data.
Double Shielded STP Cable
This type uses double protection, that is, there is a common shield for all foil cores, plus separate screen for each pair. One of the most reliable cables, several times more expensive than UTP and FTP, most often used in offices and production.
Many organizations use funny cable shielding markings. If you have to look for twisted pair cables via the Internet and in markets, you may encounter the following designations:
- F/UTP - twisted pair with common shield;
- U/UTP - completely screenless;
- SF/UTP - double shield pair;
- S/FTP - in it the overall screen is presented in the form of a copper braid, and the protection of each pair is made of foil.
As noted, the most common use case is an FTP cable, the price of which depends on the manufacturer, the shielding material used and the quality of the outer protective sheath.
Twisted pair by type of sheath used
Pairs of cores twisted together are connected into a single cable using an outer protective sheath. It is usually made of polyethylene or polyvinyl chloride. This polymer has excellent resistance to most solvents, alkalis and oils, does not emit toxic fumes in the air and does not deteriorate in the temperature range from -15 to +66 degrees Celsius.
In its pure form, it has excellent ductility, therefore, so that the cable can be easily bitten or torn lengthwise if necessary, chalk is added to the polyvinyl chloride. When paired, they make an excellent material for making a protective shell.
Various additives can be added to the two main components to provide the desired properties of the outer part of the FTP cable. Based on them, the division of the shell into types, which are distinguished by color, was constructed.
Low smoke non-flammable shell
Orange - made of non-flammable polymer, has the highest fire safety rating. Marked LSZH (stands for Low Smoke Zero Halogen - low smoke emission, zero halogens).
For outdoor use
Black - it contains the same polymer, but it has an additional protective layer made of polyethylene, which is designed to protect the cable from external atmospheric influences; usually wires with such a sheath are used for laying on the street, in sewers or in the air.
For indoor installation
Gray is a common budget sheath, used for cables laid indoors. Quite fragile to break and break, which allows you to quickly break it in the right place.
There is always a marking on the shell indicating the type of shielding, manufacturer and category. Information is applied to the FTP cable every meter, for foreign ones it can be a foot. With its help, you can easily measure the required length or find out the length of the laid lines by simple calculation.
As a rule, cables are flat and round, in everyday life and in office premises round is used (not counting telephone noodles, which can be found less and less). For its installation, boxes or cable channels are provided in the baseboards, and there are also semicircular fasteners that allow you to nail the cable to the wall without damaging it.
Cable categories by number of pairs and bandwidth
As already mentioned, there can be one twisted pair or several inside the cable. Depending on their number and bandwidth, FTP cable has different categories.
Legacy twisted pair cable categories
Cat1 - operating frequency 100 kilohertz, used for voice signal transmission, popularly called “telephone noodles”.
Cat2 - the used frequency is 1 megahertz, has the ability to transmit data up to 4 Mbit/s, contains 2 pairs of conductors, is currently not used anywhere.
Cat3 - operates at a frequency of 16 megahertz, maximum speed transmission up to 10 Mbit/s, contains 4 pairs, can be used in telephone and computer networks with a length of no more than 100 m.
Cat4 - used frequency band up to 20 megahertz, transmission speed up to 16 Mbit/s, contains 4 pairs and is not used anywhere at this moment.
Widely Used Twisted Pair Categories
Cat5e is the most popular FTP cable containing 4 pairs of conductors. Operates at a frequency of up to 125 megahertz, when using 2 pairs it provides transmission speeds of up to 100 Mbit/s, when using all pairs up to 1 Gbit/s per second.
Cat6 - operating frequency up to 250 megahertz, has 4 pairs of cores and, when all are used, provides speeds of up to 1 Gbit/s per second, at a distance of up to 50 meters it transmits up to 10 Gbit/s.
Rarely used promising categories
Cat6a - has an operating frequency of up to 500 megahertz and 4 pairs of wires, providing transmission speeds of up to 40 Gbit/s. Used to build high-speed lines.
Cat7 is a four-pair cable with an operating frequency of up to 700 megahertz and a transmission speed of up to 50 Gbit/s.
Cat7a - 4 pairs, frequency up to 1200 megahertz, can provide speeds of up to 100 Gbit/s with a length of no more than 15 meters, and up to 10 Gbit/s when using all pairs.
How to choose the right twisted pair cable for home use
The most common cable is FTP category 5e twisted pair cable. It is used to lay local networks in offices and at home, and is used to connect computers to a router or hub. And, most likely, the cable that is installed in your apartment will be of the same category.
Some providers save on twisted pair cable and pass it on to their customers budget options no shielding at all. Unshielded twisted pair can be laid inside the apartment if it is possible to lay the network away from the wiring and hide it in a cable channel.
Based on the above, we can draw a conclusion. In order to choose the right twisted pair, you need to decide on:
- Required data transfer speed.
Most providers do not offer tariffs with speeds above 100 Mbit/s. However, if your equipment allows it, you can build a local network with speeds of up to 1 Gbit/s per second.
- The need for cable shielding.
When laying the wire in the baseboard, away from electrical wiring, subwoofers and other devices that emit EMR, you can use UTP to save money. It is still recommended to use an FTP cable or at least an F/UTP cable.
- The installation location is where it takes place, outdoors or indoors.
If you're on the street, you'll have to buy a protected cable, which costs an order of magnitude more. For installation in an office, apartment or private house, it is enough to use a regular gray cable. Before installation in an office space, check the fire safety requirements.
Having studied what twisted pair is and what types it comes in, you can easily choose the cable that is suitable specifically for your conditions. Do not forget that right choice FTP cable is only half the battle; you also need to learn how to crimp correctly and how many cores to use.
For these purposes, you can also invite a specialist who will come with necessary equipment, will crimp the cable and configure all computers. Or you can check how the pressure test was done on the wire that the provider brought into the apartment, and do it in the same way.
Which cable should I use for IP CCTV cameras when designing local area networks or integrated security systems?
Purpose.
You need to choose a UTP twisted pair cable depending on your purpose. Each cable has its own purpose and will do its job better.
What kind of cable can be laid underground? Which one to use outdoors? Which one can you “start” on? Which one can be used in children's institutions/hospitals? Which one to use in crowded places: shopping centers, airports, train stations?
Explanation of twisted pair cable designations.
Please note that the wire may have several markings in different combinations, for example: FRLSLTx.
| P.E. | Cable for outdoor use (external installation). The protective outer shell consists of light-stabilized black polyethylene (SPE), abbreviated PE. Resistant to ultraviolet radiation, weather precipitation and capable of operation at temperatures in the range: -60°C to +70°C |
| Cable | Availability of cable. Allows you to lay twisted pair “air” between supports using anchor tension clamps or other devices. for a cable with a rope in the catalog. |
| TO | Armored cable. The sheath is covered with armor in the form of a braid of galvanized steel wires, which protects the cable from rodents. Suitable for laying underground. It has an index marked K (armored cover made of round steel wires). |
| PUR | The cable for installation in damp rooms and chemically aggressive environments: acids, gasoline, fats, oils, ozone, hydrolysis, water and cold - is marked: PUR, made of halogen-free thermoplastic polyurethane of orange color. |
| L.S. | Cable of reduced fire hazard, with low smoke and gas emissions, gray or white colors will suit for installation in industrial plants. |
| ng(A) | Flame retardant according to category A |
| HF | Halogen Free. The coating is made of a halogen-free polymer composition. Halogen-free wire is used in places with increased requirements for general safety: in crowded places. The cable is subject to very high requirements: the cable line must remain operational for at least 1.5 hours in the event of a fire, the protective sheath must not support combustion, and it must be absolutely safe for environment. for halogen-free cable in the catalog. |
| LSLTx | Low toxic (Loutox). Cable with low toxicity of combustion products. Designed for installation in children's buildings educational institutions, healthcare institutions and social homes. |
| FR | Fire-resistant cable, used for warning systems: evacuation control systems (ECCS), voice warning systems transmitting data over Ethernet networks |
| FRLS | Fire resistant, low smoke/gas emission. It is used for installation in office premises, industrial enterprises, and in the metro area. |
| FRHF | Fire retardant, halogen-free. It is used for installation of residential/non-residential premises, including in places with large numbers of people, as well as in premises with microprocessor technology: Data centers, server rooms. for fire-resistant, halogen-free cable in the catalog. |
| PVC | Cable for indoor use (internal installation). Has a PVC sheath, usually gray or white. It is allowed to be used outdoors, provided that it is protected from direct exposure to solar radiation and precipitation. |
| LSZH; ZH ng(A)-HF | LSZH (Low Smoke Zero Halogen, means low smoke emission, halogen-free), sometimes written as: LSOH. In Russia, according to: GOST R 54429-2011 and GOST 31565-2012, this cable will be marked: ZH ng(A)-HF. It is used when placed in the subway, industrial enterprises, office premises, high-rise buildings, complex buildings, including those with large crowds of people, premises equipped with computer and microprocessor equipment. |
| Screen | Availability of a screen. To protect against electrical noise and interference, a screen is used; it can be common for all cable cores or for each pair. The overall shield can be braided, foil, or braided and foil combined. |
| U/UTP | UTP - Unshielded twisted pair. for the cable in the catalog. |
| F/UTP | FTP - Shared foil screen. for the cable in the catalog. |
| S/UTP | STP - Total Braid Screen |
| U/FTP | STP - Foil screen for couples |
| F/FTP | FFTP - Foil shielded cable with shielded foil around each pair |
| S/FTP | SFTP - Common braided screen with foil vapor screen |
| SF/UTP | SFTP - common braided and foil shield |
| SF/FTP | SFTP - common foil and braid shield, also with foil shielded pairs |
| Category 5e | The most popular type of cable, has an operating frequency of up to 125Mhz, allows you to organize data transmission speeds of up to 100 Mbit/s (when using 4 cores: 1,2,3,6) and data transmission speeds of up to 1 Gbit/s (when using 8 cores). The cores of the central conductor can be copper or copper-plated with a diameter of 0.46 - 0.52 mm. to category 5e in the catalog. |
| Category 6 | Category 6 uses larger diameter conductors and a smaller twist pitch compared to Category 5, which helps to increase the cable capacity. Has an operating frequency of 250Mhz. Allows you to organize data transfer rates of up to 10 Gbit/s over a distance of up to 55m. to category 6 in the catalogue. |
| Category 6a | Operating frequency 500Mhz. Allows you to organize data transfer rates of up to 10 Gbit/s over a distance of up to 100 m. Used in networks: 10 Gigabit Ethernet. to category 6a in the catalogue. |
| Category 7 | Data transfer speed up to 10 Gbit/s. Operating frequency up to 700Mhz. to category 7 in the catalogue. |
| Category 7a | Data transfer speed up to 10 Gbit/s. Used in networks: 10GBASE-T. Operating frequency up to 1200 MHz. Today, it offers maximum channel width when building a network based on twisted pair. to category 7a in the catalogue. |
| +2*X | Combined twisted pair. It has additional conductive conductors: Usually, copper or aluminum, with a cross-section of 0.5-1.5 mm². Operating voltage up to 600V AC or DC. The combination cable allows you to transmit digital signal and supply power to electrical equipment (video surveillance camera, IR illumination, camera heating, DVR, switch, and other network devices). choice of combined twisted pair with additional meals in our catalogue. |
| Solid | Indicates that the twisted pair conductors are single-core (solid). Such a cable has the best wave characteristics, and the worst mechanical ones. When building video surveillance systems, it is advisable to use it. |
| Stranded or Flex | Multicore twisted pair. This cable bends better, can withstand a greater number of bends, and is recommended for use in places subject to vibration or movement: for example, on vehicles. It is also better suited for making patch cords ( in the catalog). |
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Twisted pair cable- these are one or several pairs of insulated wires twisted together with a given pitch and placed in a common plastic sheath.
When organizing cable or local networks in everyday life and small offices about the category network cable you don't have to think about it, because short distances and low speeds of information data transmission, this issue is not relevant. Networks can be made from almost any cable, plugs and RJ45 sockets that the market offers. Currently, to create computer networks, as a rule, unshielded twisted pair cable of category CAT5 is used, as it is not expensive and provides sufficient data transfer speed for the consumer. You can see the CAT5 twisted pair cable in the photo.
Categories of twisted pair lan cable are classified in the EIA/TIA-568 specification and in the international standard ISO 11801. In Russia there are two GOST R 53246-2008 (a copy of the American ANSI/TIA/EIA-568B) and GOST R 53245-2008 (developed on based on the technical regulations of one of large manufacturers twisted pair cables). On the page I have provided only part of the information from the documents that will help create computer network with knowledge of the matter.
Types of twisted pair cable shielding
The design of the twisted pair lan cable is determined by the required data transfer speed. The cable can be unshielded or shielded and is designated as follows.
The screen performs two tasks at once: it reduces the radiation of electromagnetic fields by the twisted pairs themselves into the surrounding space and protects them from external electromagnetic fields. Shielded UTP cables are used exclusively for laying trunk lines and in industrial premises with large electromagnetic fields. In homes and offices, as a rule, unshielded UTP cable is used.
Types of twisted pair cable cores
There are two types of twisted pair cores in LAN cables: single conductor and multi-core. The diameter of the cores in single-core twisted pairs is 0.51 mm. Cables with single-core conductors are used for installing networks in boxes, cable ducts and along walls. In addition, it is easier to install in communication devices.
A cable with multi-core conductors is used only where it can be subject to frequent bending, for example, connecting a computer to an RJ standard socket; they are also called patch cords. The signal attenuation in a cable made of multi-core twisted pairs is greater than that of a cable made of single-core conductors. To crimp multi-core twisted pairs you need special connectors 8P8C standard. They differ in that the teeth in the lamellas are set apart, like a saw.
Color of twisted pair cable sheath depending on purpose
The sheath of a UTP twisted pair cable is usually made of polyvinyl chloride with the addition of chalk for fragility when stripping and sometimes different colors, which indicate the scope of application.
Twisted pair cable marking
According to form lan cable Twisted pair cables come in round and flat types. On the cable sheath, every meter or foot (0.3 m) is marked, indicating the manufacturer, cable category, footage and other information. This allows you to determine the length of the laid line without a ruler.
As can be seen from the markings in the photo, this cable is designed to operate at ambient temperatures up to 75°C, UTP - without shielding, 4PR - has 4 twisted pairs, EIA/TIA-568 - complies with the EIA/TIA-568 specification, marks on the cable in feet.
Inside the sheath, parallel to the twisted pairs, you can often find a nylon thread, which serves to increase the mechanical strength of the cable as a whole, and also allows you to cut the sheath along when cutting the cable without damaging the twisted pairs. To do this, you need to free the twisted pairs from the sheath a couple of centimeters, grab the thread and pull it into reverse side. The sheath can be easily cut along the cable. This thread is also called split thread.
Cable categories twisted pair
As technological capabilities improved, the number of categories increased, and currently has reached seven. The main criterion for classifying a UTP cable into one of the categories is its high-speed capabilities for transmitting information data. Speed is measured in Mbit/sec. The larger the number, the greater the amount of information a twisted pair cable can transmit per unit time.
| Table technical parameters UTP twisted pair cable depending on their category | |||
|---|---|---|---|
| Cable category | Frequency band up to, MHz | Data transfer rate up to, Mbit/sec. | Purpose and design |
| CAT1 | 0,1 | – | Voice signal transmission, telephone “noodles” TRP |
| CAT2 | 1 | 4 | 2 pairs of conductors, not currently used |
| CAT3 | 16 | 10 | 4 pair cable for telephone and local networks up to 100 meters long |
| CAT4 | 20 | 16 | 4 pair cable, not currently used |
| CAT5 | 100 | 100 when using 2 pairs | 4 pair cable for telephone and local networks |
| CAT5e | 125 | 100 when using 2 pairs | |
| CAT6 | 250 | 1,000 when using 4 pairs, 10,000 at a distance of up to 50 meters | UTP 4 pair cable for computer networks |
| CAT6a | 500 | 40 000 | UTP 4 pair cable of high-speed Internet lines, in the future |
| CAT7 | 700 | 50 000 | S/FTP 4 pair cable high-speed Internet lines, in the future |
Twisted pairs in a lan cable have characteristic impedance 100±25 Ohm, all additional connections, including twists, change the resistance value, which reduces the data transfer speed. The impact on long sections of networks is especially relevant.
Currently, in practice, twisted pair LAN cable of category CAT5e is used everywhere to build local networks and the Internet; data is transmitted, as a rule, only over 2 pairs. orange and green.
Twisted pair cable of the sixth category CAT6
A twisted pair cable of the sixth category CAT6 is easy to distinguish from a cable of the fifth category, even without understanding the markings.
The photograph shows that the pairs of wires in the twisted pair cable of the sixth category CAT6 are arranged with a more frequent pitch and in the center of the cable there is, unlike the CAT5 cable, additional insulation between the pairs. This design allows you to reduce crosstalk and thereby increase the speed of information data transfer.
Using insulated conductors twisted in pairs. This type of cable is used in the telecommunications industry and is an integral component of structured cabling systems ().
As has already become clear, the cable got its name from the use of twisted conductors in pairs, hence the twisted pair. What does this give in technical issue? Coiling is done specifically to reduce the impact of electromagnetic interference from external sources on the pair's cores. And in category 5+ cables, the cores of each pair are twisted at different pitches to reduce interference from twisted pairs to each other.
Cable shielding is also used to protect against interference. And, in accordance with this, they are divided into two main types - shielded and unshielded. To understand what degree of shielding a cable has, you need to understand its markings.
Cable markings
When choosing a cable, you will definitely come across its special markings. One of the parts in this marking carries information about the shielding of the cable. For example: “FTP cat cable. 5e CCA” - let's figure out what the letters FTP mean in the name of this cable.
When marking cables, the following designations are used:
- TP (Twisted Pair)– type of twisting, twisted pair.
- U (Unshielded) – protective screen absent.
- F (Foiled)– foil is used as a screen.
- S (Shielded)– a wire braid is used as a screen.
According to standard ISO/IEC 11801 to mark cables, a combination of these designations written in a certain order XX/YZZ is used. Where “XX” denotes the overall shield of the cable, “Y” denotes the shield of each pair, and “ZZ” marks the type of wire twist.
But in practice, confusion arises due to the fact that manufacturers often mark cables with only three letters. What is a twisted pair cable marked UTP or FFTP? Let's take a closer look.
Most common cables UTP(no shielding) and cables FTP(all pairs are enclosed in a common foil screen).
Twisted Pair Categories
On this moment There are seven categories of twisted pair cables used. Their main difference is the cable bandwidth, which is a determining factor in the speed of information transfer and the ability to use special network technologies.
| Designation | Bandwidth | Data transfer rate |
|---|---|---|
| cat. 1 | 100 Hz | up to 56 Kbps |
| cat. 2 | 1 MHz | up to 4 Mbit/s |
| cat. 3 | 16 MHz | up to 10 Mbit/s |
| cat. 4 | 20 MHz | up to 16 Mbit/s |
| cat. 5 | 100 MHz | up to 100 Mbit/s when using 2 pairs |
| cat. 5e | 125 MHz | up to 100 Mbit/s when using 2 pairs |
| cat. 6 | 250 MHz | up to 1 Gbit/s using 4 pairs up to 10 Gbit/s with a cable length of no more than 55 m |
| cat. 6a (cat. 6e) | 500 MHz | up to 1 Gbit/s using 4 pairs up to 10 Gbit/s with a cable length of no more than 100 m |
| cat. 7 | 600 MHz | up to 10 Gbit/s using 4 pairs |
| cat. 7a | 700 - 1200 MHz | up to 10 Gbit/s using 4 pairs up to 40 Gbit/s with a cable length of no more than 50 m up to 100 Gbit/s with a cable length of no more than 15 m |
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