The low cost of twisted pairs has expanded the possibility of their use in short-range distribution systems or in-wire applications, including a local loop, wire and network terminal. Over the years, the twisted pair bandwidth for Internet needs has increased dramatically. Starting from the original 10 Mbit / s standard, progress has accelerated the network to 100 Mbit / s and further to 1 Gbit / s. More recently, 10 Gigabit Ethernet has provided the speed needed for new applications. To a large extent, these updates were caused by increased processor speeds, which allowed networks to avoid communication bottlenecks.
Internet cable standardization
Twisted pair consists of two copper wires with a thickness of about 1 mm. They are individually covered with plastic insulation and twisted into a spiral shape. Polyethylene, polyvinyl chloride, polymer resin and Teflon are substances that are used for protection purposes.
The purpose of twisting is to reduce electrical interference in the environment. Twisted pair performance or throughput improves with the number of twists per length. If two wires are located in parallel, and electromagnetic interference is generated in them, for example, from a nearby electric motor, then they occur in a wire closer to the noise source, which leads to a higher voltage level in one than in the other.
The standardization of such cables is carried out in accordance with international requirements of ISO / IEC JTC1 / SC25 / WG3, as well as organizations such as TIA / EIA - Telecommunications Industry Association in the United States.
Main categories of cables:
- 3 (10BaseT);
- 4 (10BaseT 16.0 Mbps);
- 5 (10BaseT, Token-Ring 16.0 Mbps and TPD 100.0 Mbps);
- 5e (type R evolved to a bandwidth of 100.0 MHz);
- 6 (for 200 MHz bandwidth);
- 7 (bandwidth of twisted pair 600 MHz).
They are compared in accordance with crosstalk, that is, loss of part of the signal energy due to the proximity of another circuit and its attenuation.
The effect of noise on twisted wires
Noise leads to uneven loading and signal damage, then there will be differences on the receiver side. If two wires are twisted, the cumulative effect of interference on both wires is the same, so each wire is closer to the noise source for half the time, and further away in the other half, the opposite is true in the next turn, so there will be no receiver differences because unwanted signals are suppressed.
An important condition for increasing the bandwidth of a twisted pair cable is its calibration. The sensor is a measure of the thickness of the conductor. The thicker the wire, the stronger the signal at a given distance and the better the characteristics of the medium. The effective passband of a twisted pair cable depends on several factors, including the size of the conductor, the length of the circuit, and the distance between the amplifiers (repeaters).
Twisted pair can be used to transmit an analog or digital signal, and the frequency range is from 100 Hz to 5 MHz. The most common application is the IS telephone system. Twisted pair is limited by distance. As it increases between the network elements, the attenuation increases, and the twisted pair bandwidth at a given frequency decreases.
WAN Wire Types
There are two types of twisted pairs - unshielded (UTP) and shielded (STP). UTP is made of color-coded copper wires, but does not contain a braid as an insulator to protect against interference. The wire pairs in each cable have a different number of twists per meter. There are different categories of UTP.
STP is made of pairs of copper wires that are twisted together. The pairs are covered with foil or wicker mesh, as well as an outer sheath of PVC. This foil or mesh prevents electromagnetic interference and eliminates crosstalk.
The screen must be earthed so that the foil or wicker net does not become a magnet for electricity. Twisting the wires reduces the effects of noise or external noise. The number of turns per unit length will determine the quality of the cable, and more turns mean better quality.
STP is less sensitive to noise than UTP and therefore reduces crosstalk. The disadvantages of STP are that it must be properly grounded and more expensive than UTP.
Twisted pair benefits:
- Used for transmission, like analog. and digital data.
- Relatively easy to implement.
- The cheapest way to transmit over short distances.
- If part of the cable is damaged, this does not affect the entire network.
The disadvantages of twisted pair:
- Offers poor noise immunity, resulting in greater signal distortion.
- The attenuation is very high.
- Supports lower bandwidth compared to other environments.
- Provides a speed of 10 Mbps to 100 m.
- It provides very poor security and is relatively easy to use.
- Being thin in size, they can be easily damaged.
General cable properties
The effect is manifested depending on the thickness of the conductor. The thicker the wire, the lower the resistance, the stronger the signal at a given distance and the better the characteristics of the medium. Thicker wires offer the advantage of greater tensile strength. Gauge numbers are regressive. In other words, the larger the number, the smaller the conductor.
Configuration with one pair - several pairs are combined in such a way as to minimize deployment costs associated with connecting multiple devices, for example, PBX or KTS electronic telephone exchanges, data terminals and a modem to a single workstation.
Bandwidth - The effective capacity of a twisted pair cable depends on several factors, including the size of the conductor, the length of the circuit, and the distance between the amplifiers (repeaters). An application with a high bandwidth (frequency) can interfere with other signals in pairs in the immediate vicinity.
Security - Twisted pair is inherently an unsafe transmission medium. It is relatively easy to deploy physical taps over UTP. In addition, the radiated energy is easily intercepted using antennas or inductive coils, without the need for a physical outlet.
Data rate
While cable network standards determine the throughput of an installed system, the actual speed with which data can be transmitted depends on the design of the electronic equipment connected. The system bandwidth is indicated in megahertz (MHz), and the data transfer rate is indicated in bits per second: Mbit / s or Gbit / s.
Although the twisted pair connection category defines the maximum bandwidth, the maximum data rate actually transmitted by the cable is determined by the electronic equipment of the cable system. Standardized data rates tend to increase by a factor of ten.
Cat5e cable speeds support high network performance. Enhanced Category 5 cables can provide Gigabit Ethernet speeds of up to 1000 Mbps. Cable-connected devices, including switches and routers, must also support the desired speed.
Cat5e provides 100 MHz bandwidth, although options with capacities up to 350 MHz are available. The cable provides less crosstalk and interference compared to the original Cat5. Thanks to the speed and availability of Cat5e, it is typically used on wired LANs that have high performance requirements and cost 20 percent less than Cat6.
Unshielded UTP Schema
UTP stands for unshielded cable. It is a 100 ohm copper cable that consists of 2-1800 unshielded twisted pairs surrounded by an outer sheath. They do not have a metal shield. This makes the cable small in diameter but not immune to electrical interference. A twist helps to improve its resistance to electrical noise and electromagnetic interference.
For horizontal cables, the number of pairs is usually 4 pairs. For trunk cables, the number of pairs will usually be incremented by 25, since multi-pair UTP cables are assembled into a tie group of 25 pairs. The copper conductor of both horizontal and UTP trunk cables has 22 AWG or 24 AWG. 24 AWG is the most common size, but higher performance cables such as UTP category 6 use 23 AWG copper wires.
Solid conductor cable
As the name implies, solid wire UTP cables have one solid copper conductor. In addition to being physically stronger and easier to work with, they have excellent twisted pair electrical characteristics that remain stable over a wider frequency range.
Cables with solid wires have lower DC resistance and lower susceptibility to high-frequency influences due to their diameters. These properties allow the use of single-core cables, providing longer transmission and high data rates than their multi-core analogs. UTP cables used for both horizontal and trunk applications.
Twisted UTP Cable Picture
Stranded Conductor UTP Cable Picture - Multicore cables are commonly used as patch cables in work areas or in telecommunications rooms. Inside twisted pairs of a multicore cable, each individual conductor consists of a bundle of wires of shorter length. They are arranged so that several wires surround one wire in the center of the beam, with a throughput of twisted pair 8 wires above their 4 pair.
The outer wires are spirally wound around the center wire using a process called twisting. The twisted wires together form one conductor with a total diameter approximately equal to the diameter of the conductor in a solid cable, but with a much smaller conductive area (based on the smaller diameters of the conductive wire cores). The core of conductor wires serves to protect them and provides the flexibility of multicore cables.
UTP cables are mainly used for LAN. They can be used for voice, low and high speed data, audio and paging systems, and for building automation and control systems. The UTP cable can be used both in horizontal with a twisted pair cable of 8 cores, and in trunk subsystems.
Horizontal UTP cables have an 8-position modular connector in the work area. The RJ45 connector is an 8-wire compact modular connector used to connect a UTP data cable. RJ45 sockets are designed to support certain characteristics of category 5, 5e, 6, or 6A, and therefore must correspond to the category of cable to which they are connected.
USB extension cable twisted pair
Sometimes it happens that you need to stretch the USB cable to a distance of more than 5, 15, 30 meters or even more. You can do it yourself, today there are several solutions to choose from. It all depends on the limitations of the maximum cable length, as well as its quality.
First you need to go to the USB extension options to understand the basic length limitations of such a cable. The maximum cable length between USB 2.0 devices is 5 meters, and for USB 3.x is 3 meters. When using active USB cables or repeaters, the length limit depends on whether you are using a regular USB cable with an active or not. For them, the length of the active cable for USB 2.0 is 30 meters, and for USB 3.x - 18 meters. If using a regular cable, the maximum length for a USB 2.0 twisted-pair extension cable is approximately 20 meters, and the recommended length for USB 3.x is 10 meters.
Let's say you need to connect a USB microphone or webcam from a table in the conference room to wall-mounted televisions that are 25 meters or so away. To make such a connection, use a single Hall Research device.
Ethernet Wire Comparison
Cat5e and Cat6 are two different Ethernet cables that are classified into standard categories. “Cat” refers to the “Cable Category”, and the terms “5e” and “6” refer to different standards.
The Cat5e cable is an improved version of Cat5 with increased 5e twisted pair bandwidth. Inheriting the design and 100 MHz bandwidth of its predecessor, Cat5e improves performance by introducing optimized data rate and anti-crosstalk specifications. It transfers data 10 times faster than a Cat5 cable, up to 1000 Mbps. It supports Gigabit Ethernet and is often used on a home network with varying lengths and source wiring.
Cat5e and Cat6 cable share common RJ45 cable connectors and twisted-pair copper wire design. They represent completely different Ethernet cable standards. The Cat5e RJ45 cable has lower transmission performance, and the Cat6 (cable) RJ45 is optimized with a bandwidth of 250 MHz, higher data rate and more resistant to crosstalk and noise. The following passage will be devoted to illustrating their functional differences.
Both Cat5e and Cat6 consist of 4 twisted-pair copper wires with a longitudinal divider for insulation. This design can reduce the electromagnetic interface between different wires. Compared to Cat5e, providing equal far-end crosstalk (FEXT), return loss, and insertion loss, Cat6 has lower near-end crosstalk (NEXT). Simply put, the Cat6 cable has a high SNR (Signal Noise Ratio), which provides less noise, fewer errors and higher speed and maximum twisted pair bandwidth for signal transmission.
Twisted Pair Testing
In modern telecommunication installations, cable with a large number of twisted pairs is becoming more common in the designs of the main cross-switch and intermediate cross-switch. As a result, 100-pair, 300-pair and higher pairs are common to the main and auxiliary channels. These large numbers of cables typically contain color-coded binders that identify individual 25-pair bundles.
Sometimes these binders may be incorrectly redirected to their respective positions on the block. In addition, binders may be erroneously trimmed if the cable is broken incorrectly, so you will need to test them.
Operation Algorithm:
- Before checking the bandwidth of a twisted pair cable, disconnect and cut one end of the cable and pass a tone through each 25-pair cable using a tone generator and a single-pair cross-wire.
- Cut the first pair of the first set of 25 pairs with the blunt side of the impact blade. This will prevent the cross wire from being cut. Then they move on to the second pair of the second set, the third pair of the third set and further similarly until all 25-pair sets are not cross-linked.
- Go to the opposite end of the cable using an inductive amplifier and find a tone. If all the beams are correctly passed through the block field, the tone should move along this field in the order in which the test cross line was cut.
- On a 110-wire unit, up to 600 twisted-pair cables can be tested simultaneously without using the same package of 25 pairs twice.
Ethernet evolution
Since its development in the early 1970s, Ethernet has been constantly evolving to meet the growing demands of local area networks. Initially, he used a common coaxial cable as a communication medium, but switched to unshielded point-to-point point-to-point connections that increased throughput and also switched from local area networks (LAN) to wide area networks (WAN).
The standardization of IEEE technology in 1982, along with the advent of the World Wide Web, further accelerated the growth and subsequent dominance of Ethernet in network topography. Copper media used for Ethernet transmission has also expanded to fiber and wireless to meet bandwidth and expansion needs in these growing markets.
Throughout the evolution of up to 1 Gbps Ethernet, the 8P8C eight-way connector has been the foundation of Ethernet connectivity. This remarkable copper connector is a direct descendant of the modular connectors developed by Bell Laboratories in 1972 for use in telephony applications. In network applications, it is commonly referred to as an Ethernet or RJ45 connector.
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The technical advantages of lower speeds per lane can be balanced by overloading the occupied area of the printed circuit board, which is the result of more differential pairs. This copper connector will also be limited to relatively short-term applications, although active CXP optical cable assemblies are available.
Given the tenfold jump in speed of previous Ethernet iterations, the next logical goal is 1TbEthernet, although some offer a more “modest” jump of up to 400 Gb / s. Xilinx has already described a 28nm FPGA that can support 400 Gb Ethernet. There is no doubt that Ethernet in many of its forms will continue to pose significant technical challenges, as well as the potential for expansion of connectors over the years.