With the rapid development of mobile communications, radio frequency coaxial cables used in base station systems and indoor distribution systems have also become more and more widely used. Radio frequency coaxial cables are usually used in higher frequency bands, such as the 900MHz, 1800MHz used by 2G, 800MHz used by CDMA, and the frequency above 2000MHz used by 3G. Nowadays, mobile communication is moving towards the third-generation (3G) and fourth-generation (4G) mobile communication networks. my country is also about to enter the era of 3G networks. Among the various electrical parameters of radio frequency coaxial cables for mobile communications, attenuation is an important indicator. The use frequency of 3G network will reach above 2GHz, which puts forward higher requirements on the electrical performance of the coaxial cable, that is, lower attenuation. How to ensure the attenuation of the cable in the design and production is quite important.

The main factors affecting the attenuation of radio frequency coaxial cables

1.1 “The influence of raw materials on attenuation

The raw materials that affect the attenuation in the RF coaxial cable mainly include internal

Materials such as conductor, insulation and outer conductor. Due to the high transmission of coaxial cable

The skin effect and proximity effect will be generated when the frequency current is high, and these effects

As the transmission frequency continues to increase, it increases significantly, resulting in more current

More and more towards the surface of the conductor, and along the outer surface and outer surface of the inner conductor

Transmission on the outer surface of the conductor [1], so it transmits at 3GHz and below

In the frequency band, the surface quality of the conductor, especially the surface quality of the inner conductor is the same

The influence of the transmission attenuation of the shaft cable is particularly serious.

Severe oxidation or other quality problems, which will cause the coaxial cable

The attenuation of the conductor rises sharply, so the control of the conductor surface quality is particularly important

want.

When transmitting at a lower frequency, relative to the inner and outer conductors, the insulation is attenuated

The impact of reduction is smaller, but as the frequency increases, its impact continues to increase

Large, when reaching the 2GHz frequency band, the attenuation of the medium cannot be ignored. Depend on

The insulation layer basically adopts a foamed structure. From the actual situation,

Foaming degree is the most important factor that affects the cable dielectric attenuation, characteristic impedance and other parameters.

major factor. 1.2 The influence of standing wave on attenuation

Due to the structure of the cable itself and the inevitable in the production process

Inhomogeneity, the voltage standing wave ratio must exist, and there will be transmission in radiation

The energy in the high-frequency coaxial cable, part of it passes through multiple transmissions—reversely

Shooting, the phenomenon that eventually returns to the launching end. This loss of energy‚

It is also a factor that affects the attenuation of the cable, which forms the voltage standing wave ratio (reflection)

The additional attenuation caused by αvswr. The relationship between voltage standing wave ratio and αvswr is as

1.3 The influence of cable structure on attenuation

Figure 1 is a schematic diagram of the structure of a radio frequency coaxial cable.
DOI: 10.16105/j. cnki. dxdl. 2008.06.003
The insulating layer is composed of skin-foam-skin. Without considering the phase shift,
The attenuation constant of the cable is composed of two parts: metal attenuation and dielectric attenuation
It is calculated by formula (1):

                                          RF coaxial cable structrue

(1)
In the formula, R, C, G, L are the resistance, capacitance, conductance and electrical
Sense; α metal is metal attenuation; α medium is medium attenuation; f is frequency; εD
Is the equivalent dielectric constant of insulation; δD is the equivalent dielectric loss of insulation
Angle; D0 is the equivalent outer diameter of the insulation; d0 is the equivalent outer diameter of the inner conductor; Kρ1,
Kρ2 represents the electrical conductivity when the inner and outer conductor materials are different from the standard soft copper
Resistance increase coefficient, where Kρ = ρ/ρ0, ρ is the conductor resistivity, ρ0
It is the international standard soft copper resistivity; Ke1 and Ke2 represent the inner and outer conductors respectively
It is the increase coefficient of corrugated tube relative to smooth tube, usually Ke1,
The value of Ke2 is 1.10 to 1.20.
For the insulation equivalent outer diameter D0 in the formula, the insulation equivalent dielectric constant
What kind of parameters are established for such parameters as εD and insulation equivalent dielectric loss angle δD?
Type model and accurately determine its value, which has great influence on the attenuation calculation.
Significance. The following are coaxial cables with corrugated copper tube outer conductor
And braided outer conductor coaxial cable as an example, how to calculate the specific analysis
D0, εD, δD.

2　D0, εD, δD model determination

2.1″ Coaxial cable with corrugated copper tube outer conductor

2.1.1″ Equivalent outer diameter of insulation D0

For coaxial cable with corrugated copper tube outer conductor, due to the outer conductor

The body adopts a corrugated structure, the insulating skin layer and the copper outer conductor wave

There is also a layer of air between the peaks, and the air itself is also a kind of insulation

The medium, therefore, this will inevitably affect the electrical parameters of the cable.

Therefore, this air layer must be considered when calculating the electrical parameters of the cable

Go in, to accurately calculate the performance parameters of the cable.

Due to the uneven distribution of the air layer in the cable, the crest

The thickness of the air layer at the location is large, and the thickness at the location of the wave trough is zero.

In order to facilitate calculation, the air layer is equivalent to a uniformly distributed ring

The layer is shown in Figure 2.

Figure 2 Schematic diagram of cable insulation structure

1-Equivalent air layer 　 2-Outer skin insulation layer 　 3-Foamed insulation layer 　 4-Inner skin insulation layer

The equivalent outer diameter D0 of insulation (air+insulating medium) can be adopted
Use the geometric average of the inner diameters of the crests and troughs of the corrugated copper outer conductor to approach
Approximate calculation, namely:

(2)
In the formula, D peak and D valley are outside the wave peak and wave trough of the corrugated copper outer conductor, respectively.
Diameter; d’represents the thickness of the copper outer conductor.
2.1.2 “Equivalent dielectric constant of insulation
From the above, it can be seen that the insulating layer is composed of inner skin, foam layer, outer skin and hollow.
The composition of the gas layer, therefore, the equivalent dielectric constant of the insulation is the four-layer string
Equivalent dielectric constant of the connection.
(1) The equivalent dielectric constant of mixed insulation εr1 (using volume plus
Weighted calculation method) calculation.

In the formula, εx is the dielectric permittivity of the insulation; νx is the mixed volume of the insulation.

(2) Calculation of the equivalent dielectric constant εr2 of the foamed insulating layer.

In the formula, “p” is the foaming degree of the insulation.

(3) Calculation of the dielectric constant of the equivalent insulating layer. According to capacitance
The series relationship, the relationship between the total equivalent capacitance and the capacitance with insulation is:

Substituting the calculation formula of each capacitor into formula (5), we can get:

In the formula, εr3 is the dielectric constant of the equivalent insulating layer; ε inner, ε bubble, ε outside,
ε air is the insulating inner skin layer, foam layer, outer skin layer and air layer;
D1, D2, D3 and D0 are the outer diameters of each layer of insulation (see Figure 2).
2.1.3 “Equivalent dielectric loss tangent of insulation
(1) The equivalent dielectric loss tangent of the hybrid insulation tgδr1 (using
Use volume-weighted calculation method) to calculate.

In the formula, tgεx is the tangent of the dielectric loss angle of the insulation.

(2) Calculation of equivalent dielectric loss tangent tgδr2 of foamed insulation.

(3) The equivalent dielectric loss tangent of the equivalent insulating layer tgδr3
calculate. According to the series relationship of loss resistance, the total loss resistance is
The sum of the loss resistance of the edge layer:

Ｒtotal＝Ｒinner＋Ｒfoam＋Ｒouter＋Ｒempty

In the formula, R is always the total loss resistance; R inner, R bubble, R outer and R air are respectively
The loss resistance of each layer of insulation. Since the air dielectric loss is zero, so
The loss resistance of the air layer R air = 0, substituting into equation (10), we can get:

Ｒtotal＝Ｒinner＋Ｒfoam＋Ｒouter

In the formula, C inner, C bubble, C outer, and C air are the insulation capacitances of each layer; tgδ inner,
tgδ bubble and tgδ outside are respectively the dielectric loss tangent of each layer of insulation.

2.2″ Braided cable

　　For braided outer conductor cables, the outer conductor is made of aluminum-plastic composite screen
Masking tape + metal braided wire, aluminum-plastic composite shielding tape is generally used
It is a single-sided plastic-coated aluminum, the aluminum layer is close to one side during the production process
Insulation. Due to the skin effect and proximity effect, the outer conductor
The conducted AC current is concentrated on the inner surface of the outer conductor, that is, concentrated on the
The inner surface of the aluminum layer of the aluminum-plastic composite shielding tape.

Conductor skin effect can use electromagnetic field (current) to guide the body
The degree of penetration is expressed as, when the internal electromagnetic field of the conductor is reduced to the surface
The depth when the value is 1/e (e = 2.71828) times the penetration depth θ1‚
Its value can be calculated by the following formula:

1 times the penetration depth is

The concentration of AC current within 1 times the penetration depth is:

The penetration depth of n times is:

The concentration of AC current in n times the penetration depth is:

In the formula, θ1 and θn are respectively 1 and n times the penetration depth; σ is the conductor
The conductivity; μ is the permeability of the conductor. According to the above formula, in frequency
When the rate f=900MHz, calculate the current transmission through the aluminum layer
Into the depth and current concentration (see Table 1).

Table 1 　 f = 900MHz when the penetration depth of the aluminum outer conductor and
Current concentration degree [2]

It can be seen from Table 1 that when the frequency is 900MHz, the thickness of the aluminum layer
When the penetration depth reaches 5 times the penetration depth of the current, the AC current will have
More than 99% of the current is concentrated in the aluminum layer. This penetration depth can
Ensure the transmission characteristics of the cable. In the actual manufacturing of cables, usually
The thickness of the aluminum-plastic composite shielding tape used is 0.035mm, in which the aluminum layer
The thickness is 0.020mm, when the frequency is 900MHz, the thickness of the aluminum layer
More than 7 times the current penetration depth, which can guarantee 99.9% of the electricity
The flow can be concentrated in the aluminum layer for transmission. It can be seen from equation (13) that
The higher the frequency, the more obvious the conductor skin effect. It can also be said that the current 2G
The 1800MHz frequency band used and the 2000MHz that 3G will use
The above frequency bands, the skin effect is more obvious, and the transmission effect is better.

The coating layer of the aluminum-plastic composite shielding tape is a layer of insulator; metal
The main function of braided wire is shielding and does not participate in the transmission of AC current.
For braided cables, in fact, the outer conductor is only aluminum-plastic composite
The aluminum layer in the shielding tape.
The attenuation calculation of braided cable can also be calculated by formula (1), but relative to
For the corrugated outer conductor coaxial cable, the equivalent insulation layer has no air layer.

Accurate calculation of coaxial cable attenuation, design and development of cables,
The quality control of cables is of great significance. For wrinkled copper tubes
For the outer conductor coaxial cable, you can slightly adjust the cable
Structure to control the attenuation. Of course, the premise is that the electricity cannot be affected.
The installation and use of the cable, for example: it can be ensured that the conductor
These parameters directly affect the cable installation
Under the components, it is appropriate to change the outer diameter of the insulation or the depth of the trough of the outer conductor, etc.
Factors to adjust the attenuation parameters of the cable. Also need in the design and production process
Other electrical parameters such as impedance, standing wave, speed ratio, and cable adjustment should be considered.
Body structure stability, etc.

Cable attenuation is an important indicator to measure the level of cable quality.
It is the foundation to ensure the optimization of theoretical attenuation in the cable structure design stage.
At the same time, the impact of other factors on the attenuation of the finished cable cannot be ignored.
Noise, such as the return loss caused by the unevenness of the cable structure.
Causes the cable attenuation to deteriorate; the cable and the design match poorly
Wave loss, lead to large cable test attenuation; raw material quality, temperature
The influence on attenuation and other factors may make the actual test of the cable
The attenuation is greater than the theoretical attenuation.

For more questions, you are welcome to contact zhuhai hanqin cable co.,ltd or email: info@hanqin-cable.com

 

 

 

 

 

Hello, everyone, welcome to Zhuhai hanqin cable co.,ltd  ,in this article, we are going to discuss the CAT7 cable standard.

 

Although the Category 7 line standard has not been officially released, there are already many drafts, and many companies with strong technical strength have released products based on Category 7 wiring systems, such as AMP (AMP) and Simon. The CAT7 cable standard is a set of cabling standards that support transmission with a bandwidth of up to 600 MHz on 100 twisted-pair cables. In September 1997, ISO/IEC formally confirmed the development of Category 7/Class F cabling standards.

1. CAT7 standard basis

Compared with Category 4, Category 5, Category 5 Super, and Category 6, Category 7 has a higher transmission bandwidth, at least 600 MHz. Not only that, the seven-category wiring system is different from the previous wiring system. It is no longer a cheap unshielded twisted pair, but a double-shielded twisted pair. There have also been major changes in the network interface. When the seven types of standards were formulated, a total of eight types of connectors were proposed, two of which were RJ styles and six were non-RJ styles. In January 1999, the ISO technical committee decided to select an RJ and a non-RJ type interface for further research. At the ISO/IEC JTC 1/SC 25/WG3 working group meeting in August 2001, the ISO organization reaffirmed that the seven types of standards are divided into RJ-type interfaces and non-RJ-type interfaces. Among them, the feasibility of the RJ type interface is being reviewed and studied by the IEC SC488 organization. On July 30, 2002, the TERA seven-category connector developed by Simon Company was formally selected as the standard mode of the non-RJ-type seven-category standard industrial interface. The transmission bandwidth of the TERA connector is as high as 1.2 GHz, which exceeds the transmission bandwidth of the seven types of standards currently under development of 600 MHz. It can simultaneously support voice, high-speed network, CATV and other video applications.

The non-RJ type seven wiring technology completely breaks the traditional 8-core modular RJ type interface design, and is free from the limitation of the RJ type interface. It not only enables the transmission bandwidth of the seven types to reach 1.2GHz, but also creates a brand-new 1, 2, 4 pairs of modular form. This is a new type of interface form that satisfies wire-pair and wire-pair isolation, is compact, highly reliable, and easy to install. For example, the TERA connector can provide excellent transmission bandwidth, which exceeds the transmission bandwidth of the 600 MHz Category 7 standard currently under development. This allows some applications that require high bandwidth, such as broadband video applications up to 862 MHz, to run in Category 7/Class F cabling systems.

Due to the compact design of TERA and the modular multiple connection plugs of 1, 2, and 4 pairs, a single Category 7 channel (4 pairs of lines) can simultaneously support mixed applications such as voice, data and broadband video and multimedia, which makes it possible in the same A variety of applications can be managed in the socket, reducing the previously necessary fiber, coaxial, and twisted pair cable requirements, thereby reducing the cost of high-speed LAN equipment.

2. The main advantages of Category 7 lines

Compared with the existing Category 5 and Category 6 twisted-pair cabling systems, the Category 7 wiring system has the following obvious advantages.

• At least 600 MHz transmission bandwidth

(2) The minimum transmission bandwidth specified in the seven types of standards is 600 MHz, and the use of non-RJ type seven wiring technology can reach 1.2 GHz. And it is required to use double-shielded cables, that is, twisted-pair cables that are individually shielded for each pair and also shielded as a whole to ensure the best shielding effect, see Figure 3-5(b). The powerful noise immunity and extremely low external radiation performance of this seven-category system make the high-speed local area network (LAN) do not require more expensive electronic equipment for complex coding and signal processing.

Compared with Category 6 and Category 5, non-RJ Category 7 has higher transmission performance requirements. Category 6/Class E is currently the technology that provides the highest transmission performance without using a separate pair of shielding form. For most commercial applications, the 250 MHz bandwidth of Category 6/Class E is sufficient for users throughout the life of the cabling system. Therefore, Category 6/Class E is the best choice for commercial building wiring. The target of Category 7/Class F is better than the performance of every transmission parameter of any balanced cable.

Double-shielded Category 7 cables have a much larger outer diameter than Category 6 cables, and are not as flexible as Category 6 cables. This requires special care when designing the installation routing and termination space, leaving a lot of space and a large bending radius. In addition, the two are also different in connection hardware. The seven types of standards under development require connectors to provide at least 60 dB of crosstalk isolation between pairs of wires at 600 MHz. This requirement is 32 dB more stringent than the requirements of Category 5

at 100 MHz, and at 250 dB than Category VI. The requirement of MHz is 20 dB, so the seven categories have strong anti-interference ability.

(2) Cost saving

People may have this question: Since non-RJ type 7 wiring can achieve the transmission performance of optical fiber, why not use optical fiber to replace non-RJ type 7 wiring system? The most important thing for users is cost.

Compared with the total cost of an optical fiber local area network, non-RJ type seven wiring has obvious advantages. A cost for the installation of 24 SYSTEM 7 (SYSTEM 7 adopts double shielded TERA connectors, a standard twisted-pair cabling system solution with a transmission performance of up to 1 GHz per pair) and 62.5/125 μm multi-mode fiber channel system installation After comparative research, it is found that the installation costs of the two are similar. But the cost of a fiber optic LAN device is about 6 times that of a twisted pair device. When considering the total cost of local area network installation, SYSTEM 7 can not only provide high bandwidth, but its cost is only half of that of multimode fiber.

On the other hand, the non-RJ type 7/F grade has functions that the optical fiber does not have. Since each pair of the non-RJ type 7/F level is individually shielded, the crosstalk between the pairs is greatly reduced, which allows the SYSTEM 7 to support voice, data, and video multimedia applications in the same cable. In the work area or telecommunications room, TERA has 1, 2, and 4 modular connection plug forms, which realize the direct connection of multiple application equipment ports in the same socket.

(3) Widely used

Since the non-RJ type seven wiring system uses double-shielded cables, it can meet the needs of those regions where shielded twisted-pair systems are mainly used, such as some European and Asian markets. The dual-shielding solution is mainly used in environments with severe electromagnetic interference, such as some broadcasting stations and radio stations. In addition, it can also be used in environments that require extremely low electromagnetic radiation for safety purposes. In addition, broadband smart communities and commercial buildings are also potential markets. The capacity of a Category 7 cable can meet the requirements of all twisted-pair cabling systems, including the replacement of coaxial cable, which is not restricted by the shared sheath, while enjoying high performance and low cost.

At present, Simon is ahead of other peers in the application of seven types of standards. According to Simon Company, Simon Company has created a new era in the commercial application of seven types of wiring. Simon’s TERATM breaks the shackles of the traditional 8-core modular RJ-type interface design and creates a brand-new structure. With incomparable performance and 1, 2 and 4 pairs of modular forms, from the limitations of the RJ-type interface Freed up, so that the transmission bandwidth of the seven categories reached 1.2 GHz. Simon’s SYSTEM7SM solution adopts TERATM connector, which can provide excellent transmission bandwidth, which far exceeds the transmission bandwidth of the current standard 600 MHz Category 7 standard. This capability enables some applications that require high bandwidth, such as broadband video applications up to 862 MHz, to run in Category 7/Class F cabling systems and use the same connection with other network applications. For example, it can support 3 kinds of mixed applications on a single seven types of channels (4 pairs of lines), and support voice, data, and broadband video multimedia applications at the same time.This new technology makes it possible to support all applications on twisted-pair cabling, including those that previously required optical fiber and coaxial transmission. The powerful noise immunity and extremely low external radiation performance of the seven types of systems make more advanced high-speed LANs do not require more expensive electronic equipment for complex coding and signal processing. The seven-category TERATM connector developed by Simon company provides continuous high-performance margin and linear frequency response up to 1 GHz, and the termination time is short, the volume is small, and the RJ type 8-core interface occupies the same space size.

 

 

Welcome to Jiexi Kunlian Cable Co.,Ltd   , we will discuss some knowledge of feeder cable connectors

                                           

Introduction of connectors:

Feeder connector (connector) and conversion head (adapter)

1. Feeder connector (connector)

A detachable radio frequency connector is generally used for connection between the feeder and the equipment and different types of cables. Connectors are commonly known as joints.

Common RF connectors are as follows:

1. DIN type connector

The applicable frequency range is 0~11GHz, which is generally used for the radio frequency output port of macro base stations.

2. N type connector

The applicable frequency range is 0~11GHz, and it is used for small and medium power coaxial cable connectors with threaded connection mechanism.

This is the most widely used connector in indoor distribution. It has good mechanical properties and can be used with most feeders.

3. BNC/TNC connector

BNC connector

The applicable frequency range is 0~4GHz. It is a coaxial cable connector with bayonet connection mechanism for low power. This connector can be quickly connected and disconnected, has the characteristics of reliable connection, good vibration resistance, and convenient connection and separation. It is suitable for frequent connection and separation occasions and is widely used in radio equipment and test instruments to connect coaxial radio frequency cables.

TNC connector

The TNC connector is a modification of the BNC connector, which uses a threaded connection mechanism to connect coaxial cables in radio equipment and test instruments. The applicable frequency range is 0~11GHz.

4. SMA connector

The applicable frequency range is 0~18GHz. It is an ultra-small, suitable for semi-rigid or flexible radio frequency coaxial cable connection. It has the characteristics of small size, superior performance, high reliability, and long service life.

However, the ultra-small connectors are easily damaged in engineering and are suitable for microwave applications that require high performance, such as the internal connection of microwave equipment.

5. Inverted connector

Usually a pair of connectors: the male connector is connected by internal thread, the female connector is connected by external thread, but some connectors are opposite, that is, the male connector is connected by external thread, and the female connector is connected by internal thread. Collectively referred to as inverted connectors.

For example, the external antenna interface of some WLAN AP devices uses reverse SMA connectors.

2. Conversion head (adapter)

Our commonly used 1/2 feeder head is the N-type J head, also known as the N-J head
The commonly used 7/8 heads in the room divider are DIN-NJ heads, that is, the feeder end is DIN-sized and the output end is NJ head.

It should be a 1/2″ DIN male connector, said separately, the front is the feeder end, and the back is N and DIN.

The DIN header is used to connect to the base station, and is used when coupling the base station;

N head is divided into rooms.

Cables : There are mainly ordinary cables (8D, 1/2”, 1/2” super flexible, 7/8, 7/16”, 13/8”) and leaky cables (13/8”, 5/4”),
8D, 1/2″ super flexible, mainly used as a jumper, in some cases, bends in the complex area of the building structure.

In indoor distribution, 1/2″ and 7/8″ feeders are generally used for signal transmission. 7/16 base stations are used more often, and 13/8 is occasionally used as a backbone in large venues.
Leaky cables are generally used in tunnels.

Connectors : According to the wire diameter, it is divided into male and female heads, mainly J, K, N, D, etc., and SMA is also used in indoor distribution, which is the kind of small yellow color often seen on base stations and fiber optic equipment .

■Device name                     ◆Device model                     ●Unit                     ▲Alias
Connector Adapter                       1/2-NJ type connector   pcs                         male
Connector Adapter                 7/8-NJ type connector         pcs                          male

Connector Adapter                1/2-NK type connector          pcs                         female
Connector Adapter                7/8-NK type connector          pcs                         female

Connector Adapter               NJKW Adapter One                pcs                         Right Angle Adapter/Elbow

Connector Adapter                N Type J-J Adapter                pcs                         Unit Male to Male
Connector Adapter                N Type K-K Adapter,               pcs                        Female to Female

Connector Adapter                NJ-DINJ type adapter             pcs                         N male to DIN male
Connector adapter                 NJ-DINK type adapter            pcs                         N male to DIN female

 

Load                10W-NJ type load
Flame-retardant feeder             1/2 feeder ordinary flame-retardant type    meter
Flame-retardant feeder            7/8 feeder ordinary flame-retardant type     meter

1/2″ feeder size: 1.27cm
7/8″ feeder size: 2.2225cm
13/8″ feeder size: 4.1275cm
(Note: 1″=1in=1inch=1inch=2.54cm=0.0254m)

a) The host/extension, antenna, coupler and power splitter interfaces are N-K sockets, and the feeder is N-J sockets;
b) When the feeder connector is connected to the main unit/extension, antenna, and coupler connector, the 50mm long feeder must be kept straight out from the feeder connector before turning;
c) When the feeder connector is connected to the host/extension, antenna, and coupler connectors, the connection must be reliable, and the connector must enter the wire smoothly and must not be savagely twisted.

75-3 and 75-5 video line parameters

Coaxial cable has the advantages of being cheaper and more convenient to lay (compared to optical fiber). Therefore, generally in a small-scale monitoring system, because the transmission distance is very short, the coaxial cable is used to directly transmit the monitoring image to the image. The damage to the quality is not large, and it can meet the actual requirements.

However, according to the analysis of the characteristics of the coaxial cable itself, the attenuation of the signal when it is transmitted in the coaxial cable is related to the transmission distance and the frequency of the signal itself. Generally speaking, the higher the signal frequency, the greater the attenuation. The bandwidth of the video signal is very large, reaching 6MHz, and the color part of the image is modulated at the high end of the frequency. In this way, when the video signal is transmitted in the coaxial cable, not only the overall amplitude of the signal is attenuated, but also the attenuation of each frequency component varies greatly. , Especially the maximum attenuation of the color part. Therefore, the coaxial cable is only suitable for short-distance transmission of image signals. When the transmission distance reaches about 200 meters, the image quality will be significantly reduced, especially the color becomes dim and there is a sense of distortion.

In engineering practice, in order to extend the transmission distance, a coaxial amplifier is used. The coaxial amplifier has a certain degree of amplification for the video signal, and can also compensate different frequency components in different sizes through equalization adjustment, so that the distortion of the video signal output by the receiving end is as small as possible. However, coaxial amplifiers cannot be cascaded indefinitely. Generally, only 2 to 3 coaxial amplifiers can be cascaded in a point-to-point system. Otherwise, the video transmission quality cannot be guaranteed and adjustment is difficult. Therefore, when using coaxial cables in a monitoring system, in order to ensure a better image quality, the transmission distance range is generally limited to about four or five hundred meters.

In addition, coaxial cables still have some shortcomings in the transmission of image signals in the monitoring system:
1) The coaxial cable itself is greatly affected by climate change, and the image quality is affected to a certain extent;
2) The coaxial cable is relatively thick, which is not convenient for wiring in intensive monitoring applications;
3) Coaxial cables generally can only transmit video signals. If the system needs to transmit control data, audio and other signals at the same time, additional wiring is required;
4) Coaxial cable has limited anti-interference ability and cannot be used in strong interference environment;
5) The coaxial amplifier also has the disadvantage of difficulty in adjustment.

2. Twisted pair

Twisted-pair cables have been used for a long time. Telephone transmission uses twisted-pair cables. Twisted-pair cables are used in many industrial control systems, places with high interference, and long-distance transmission. The local area network we use today is also used. Twisted pair. The reason why twisted pair is so widely used is that it has many advantages such as strong anti-interference ability, long transmission distance, easy wiring, and low price. Since the twisted pair also has a large attenuation of the signal, when the transmission distance is long, the frequency of the signal cannot be too high.

High-speed signals such as Ethernet can only be limited to within 100m. For video signals, the bandwidth is up to 6MHz. If it is transmitted directly in twisted pair, the attenuation will be great. Therefore, the video signal must be amplified and compensated for long-distance transmission on twisted pair. Twisted pair video transmission The equipment accomplishes this function. After adding a pair of twisted pair video transceiver equipment, the image can be transmitted to 1 to 2km. Twisted-pair and twisted-pair video transmission equipment are very cheap, not only did not increase the cost of the system, but when the distance increased, the cost was much lower than that of coaxial cable. Therefore, the use of twisted pair for transmission in the monitoring system has obvious advantages:

1) Long transmission distance and high transmission quality. Due to the advanced processing technology used in the twisted pair transceiver, it perfectly compensates for the attenuation of the twisted pair to the video signal amplitude and the attenuation difference between different frequencies, and maintains the brightness and color of the original image and the real-time performance. When the transmission distance reaches 1km or more, the image signal is basically without distortion. If the relay mode is adopted, the transmission distance will be longer.

2) Convenient wiring and high cable utilization. A pair of ordinary telephone lines can be used to transmit video signals. In addition, any pair of Category 5 unshielded twisted pairs that are widely laid in buildings can transmit one video signal without additional wiring. Even if it is rewiring, Category 5 cables are easier than coaxial cables. In addition, a category 5 cable has 4 pairs of twisted pairs. If a pair of wires is used to transmit video signals, the other pairs can also be used to transmit audio signals, control signals, power supply or other signals, which improves the cable Utilization rate, while avoiding the trouble caused by separate wiring of various signals, and reducing the project cost.

3) Strong anti-interference ability. Twisted-pair cable can effectively suppress common-mode interference. Even in a strong interference environment, twisted-pair cable can transmit excellent image signals. Moreover, the use of several pairs of twisted pairs in a cable to transmit different signals respectively without interference with each other.

4) High reliability and easy to use. Utilize twisted pair cable to transmit video signals, and a dedicated transmitter must be connected at the front end, and a dedicated receiver must be connected at the control center. This kind of twisted-pair transmission equipment is cheap and easy to use. It does not require professional knowledge or much operation. It is installed once and works stably for a long time.
5) The price is cheap and it is convenient to obtain materials. Because it uses the common category 5 unshielded cable or common telephone line that is widely used at present, it is easy to purchase and the price is very cheap, which brings great convenience to engineering applications.
2. Technical performance analysis

1. Coaxial cable

In monitoring systems, it is common to use 75Ω, -5 coaxial cables. Generally, the distributed capacitance of this kind of coaxial cable is about 50-60pF/m, and the DC resistance of the cable will attenuate the transmitted signal. Tests show that a signal with a frequency of 5MHz will be attenuated by about 5dB when transmitted within a 75Ω, -5 coaxial cable for 100m. The higher the signal frequency, the greater the attenuation. The image signal is a high-frequency broadband signal. The color part of the image is located at the high end of the frequency. When the color image signal is transmitted by a coaxial cable, its brightness and color will be attenuated, especially as the transmission distance increases. It will be faded or even distorted. Tests in the laboratory found that when the color image signal is transmitted within a 75Ω, -5 coaxial cable for about 200m, its amplitude and color have been significantly attenuated. If you want to transmit longer distances, you can only add a coaxial video amplifier. The following figure shows the laboratory test waveform when a 75Ω, -5 coaxial cable transmits a distance of 200m. 2. Twisted pair
When using twisted-pair cables as the transmission medium, generally used Category 5 UTP cables are generally used. Its characteristic impedance is around 100Ω
On the right, the distributed capacitance is about 15pF/m. Unlike the coaxial cable, the signal is transmitted in a balanced manner in the twisted pair, but it will also be attenuated.

The attenuation curve of the video signal when the transmission distance is about 150m. When using twisted-pair cable to transmit image signals in the monitoring system, twisted-pair video transmission equipment should be used. Its main function is to complete balanced-unbalanced conversion , impedance matching, and With functions such as amplification and compensation, the use of twisted-pair video transmission equipment and twisted-pair cable can ensure high-quality transmission of video signals within a distance of 1.5Km. In the laboratory, a special instrument was used to test the performance indicators of the twisted pair transmission image signal, and the results are as follows:

(1) When the transmission distance is 300m, the index: DG≤1%; DP≤1°; SNR≥65dB
The 17th line test waveform:
(2) When the transmission distance is 1200m, the index: DG≤2%; DP≤2°, SNR≥60dB
The test waveform of line 17 is as follows:
1. Twisted pair cable
Twisted pair cable (hereinafter referred to as twisted pair) is a transmission medium formed by encapsulating one or more twisted pairs in an insulating jacket. It is currently the most commonly used wiring material for local area networks. In order to reduce the degree of signal interference, each pair of twisted pair in the cable is generally formed by twisting two insulated copper wires, and the twisted pair is also named. Twisted pair cables are generally used for the wiring connection of a star network. RJ-45 heads (crystal heads) are installed at both ends to connect the network card and the hub. The maximum network cable length is 100 meters. Repeaters can be installed between the twisted wires, and up to 4 repeaters can be installed. For example, if 4 repeaters are installed to connect 5 network segments, the maximum transmission range can reach 500 meters.

Twisted pair cables are divided into two categories: unshielded twisted pair (UTP) and shielded twisted pair (STP). In the local area network, unshielded twisted pair cables are divided into categories 3, 4, 5 and super 5. Twisted pair cables are divided into two types: Category 3 and Category 5.
At present, the twisted-pair cables commonly used in local area networks are generally unshielded, Category 5, 4-pair (ie, 8 wires) cables. The transmission rate of these twisted pairs can reach 100Mbps.
The outer protective rubber of Category 3 twisted pair on the market is thin, the rubber is marked with “CAT 3”, and the outer carton is marked with “Category 3”, the price is lower; the outer protective rubber of Category 5 twisted pair Thick, “CAT 5” is marked on the rubber, and “Category 5” is marked on the outer carton. The price is higher. When buying, do not buy low-quality Category 5 twisted-pair cables for cheap. These products can often only be used as Category 3 twisted-pair cables.
Category 5 twisted pair is an unshielded twisted pair. Compared with ordinary Category 5 twisted pair, Category 5 twisted pair has a smaller attenuation and stronger anti-interference ability when transmitting signals. In a 100M network, the user equipment The degree of interference is only 1/4 of that of ordinary Category 5 lines, which is a solution for future network applications, and there are few applications at present.

2. Coaxial cable
A coaxial cable is composed of a hollow outer cylindrical conductor and an inner wire located on the central axis. The inner wire and the cylindrical conductor and the outside are separated by insulating materials. According to the different transmission frequency bands, coaxial cables can be divided into two types: baseband coaxial cables and broadband coaxial cables. According to different diameters, coaxial cables can be divided into thick cables and thin cables.
Thin cables have developed rapidly in recent years, so computer local area networks generally use thin cables for networking unless there are special requirements. Thin cables are generally used for bus-type network wiring connections. Use the T-type BNC interface connector to connect the BNC interface network card, and terminal resistors need to be installed at both ends. The maximum length of each trunk line of the thin cable network is 185 meters, and each trunk line can access up to 30 users. If you want to widen the network range, you need to use a repeater, such as using 4 repeaters to connect 5 network segments, so that the maximum distance of the network can reach 925 meters.
The installation of thin cables is easier and the cost is lower. However, due to the limitation of the network wiring structure, its daily maintenance is not very convenient. Once a user fails, it will affect the normal work of other users.

Thick cables are suitable for the network trunks of larger LANs, with longer wiring distances and better reliability. Users usually use external transceivers to connect to the network trunk. The length of each section of the thick cable LAN can reach 500 meters, and the maximum length can reach 2500 meters after connecting 5 network segments with 4 repeaters. If you use a thick cable to connect directly to a network card, the network card must have an AUI interface (15-pin D-type interface). Although using thick cables to build a local area network has higher performance and larger transmission distance, it is difficult to install and maintain the network, and the cost is higher.

Impedance 75 ohms What does Level 3 mean? What does 64 conductors mean? +AL refers to aluminum foil. 1) SYV75-3, 5, 7, 9…, 75 ohm, polyethylene insulated solid coaxial cable. In recent years, some people call it “video cable”;
2) SYWV75-3, 5, 7, 9…75 ohm, physical foamed polyethylene insulated coaxial cable. Some people call it “RF cable”

3) Basic performance:
l SYV physical structure is 100% polyethylene insulation; SYWV is a physical foamed polyethylene insulated cable with a foaming rate of 70-80%;
l Due to dielectric loss, the attenuation of SYV solid cable is obviously greater than that of SYWV physical foamed cable; among commonly used engineering cables, physical foamed cables are still the cables with the best transmission performance and the lowest price, in video, radio frequency, and microwave bands. It’s all like this. The test data given by the manufacturer also illustrates this point;
l Coaxial cables can be used in DC, RF, and microwave bands. Differentiating cables according to “RF”/”video” is not only insufficient, but also easy to mislead: it seems that video transmission must or can only choose solid cables (choose the ones with large attenuation and high prices?); from the perspective of engineering applications, or It is more practical to distinguish the types according to “solid core” and “foamed” cables;
l The difference between the characteristics of high-stranded (128) and low-stranded (64) cables: experimental research by eie laboratory shows that in the frequency band below 200KHz, the “low resistance” of the shielding layer of high-stranded cables plays a major role, so low-frequency transmission attenuation is less than that of low-stranded cables. cable. However, in the video, radio frequency, and microwave bands above 200-300KHz, because the “high frequency skin effect” plays a major role, the high braided cable has lost the advantage of “low resistance”, so the high frequency attenuation of the two cables is basically the same.

1. The thinner the cable, the greater the attenuation: For example, the attenuation of the 75-7 cable at 1,000 meters is roughly equivalent to the attenuation of the 75-5 cable over 600 meters, or the transmission effect of the 1000-meter 75-7 cable is the same as that of the 75-5 cable over 600 meters. The transmission effect is roughly equivalent;
2. The longer the cable, the greater the attenuation: For example, the “decibel” of the 6M frequency attenuation of the 75-5 cable is 750 meters, which is 75% of the “decibel” of the attenuation at 1000 meters, which is 15db; 2000 meters (1000+1000) attenuation It is 20+20=40db, the calculation method of other frequency points is the same. According to the above 1000-meter cable test data, when calculating the attenuation of cables of different lengths, please remember that “decibels are based on the relationship of adding alkali” or “decibels of attenuation can be calculated according to the percentage relationship of length change”, and you can use it flexibly;
3. Frequency distortion characteristics: low-frequency attenuation is reduced, and high-frequency attenuation is large. The difference between the high/low side frequency attenuation can be called the “side frequency difference”, which is a very important parameter. The longer the cable, the greater the “side frequency difference”; fully understanding and mastering the “frequency distortion characteristics” of the coaxial cable is of great significance in engineering; this is the most critical characteristic that affects the image quality, and it is also The most overlooked problem in the project;

When building a network, most people will pay attention to equipment such as switches, routers, and network cards, but they are generally not too picky about network cables. However, with the expansion of network scale and the increase in demand for network cables, the importance of network cables has become increasingly obvious. So what types of network cables are there, what are the differences between different network cables for data transmission, and how to choose a network cable when building a network?

1、Network cable type

network cable mainly divide into three kinds, “twisted pair”,”coaxial cable”,”fiber optical”

Twisted pair

Twisted pair (TP) is one of the most commonly used transmission media in integrated wiring projects. It is generally formed by two 22-26 gauge insulated copper wires entwined with each other. The name “twisted pair” is also derived from this . Its characteristic is that it is cheap, so it is widely used, such as our common telephone lines. It is used to connect with RJ45 crystal headTwisted pair cable can be divided into unshielded twisted pair (UTP) and shielded twisted pair (STP). The outer layer of the shielded twisted pair cable is wrapped with aluminum platinum to reduce radiation, but it cannot completely eliminate the radiation. The price of shielded twisted pair cable is relatively high, and installation is more difficult than that of unshielded twisted pair cable. Unshielded twisted pair cable has the following advantages:

Unshielded jacket, small diameter, saving space occupied; light weight, easy to bend, easy to install; stringing the proximal end

Disturbance is minimized or eliminated.

Twisted pair cables are from category 1 to category 7, and the positioning network is different, and the transmission rate is also different.

Coaxial cable

Coaxial cable refers to a cable with two concentric conductors, and the conductor and the shielding layer share the same axis. It is a kind of network cable. The most common coaxial cable consists of a copper conductor isolated by an insulating material. Outside the inner insulating material is another layer of ring conductor and its insulator, and then the entire cable is covered by a polyvinyl chloride or Teflon material sheath. .

Optical Fiber

Optical cables are manufactured to meet optical, mechanical or environmental performance specifications. It is a communication cable assembly that uses one or more optical fibers placed in a sheath as a transmission medium and can be used individually or in groups. An optical cable is a communication line in which a certain number of optical fibers compose a cable core in a certain manner, and are covered with a sheath, and some are also covered with an outer sheath to realize the transmission of optical signals.

What is the difference between a network cable and a telephone line? Can they be shared?

• different roles

1、The telephone line uses ADSL to modulate the computer’s digital signal into an analog line number and spread it through the telephone line. After reaching the opposite end, which is the telecommunications side, the analog signal is demodulated into a digital signal. The network cable access to the Internet lacks the step of modulation and demodulation.

2、Bandwidth issues. The telephone line is affected by the physical bandwidth, and generally the bandwidth is not too high (the maximum bandwidth is

8M), the physical bandwidth of the network cable is relatively high (a good network cable can reach 1000M or more).

（2）Different interface：

Why is the phone interface connected with the cat, but the network cable interface has no response when it is connected? This is because the signal from the phone line needs to be converted and processed by the cat to be forwarded to the network equipment, such as forwarding to the computer, router, Hubs and switches, etc. If it is connected directly, it is an unrecognizable analog signal, which is equivalent to no signal. In other words, the role that the cat plays in the middle is signal conversion and simple processing. Specifically, it converts the analog signal from the telephone line into a digital signal to the network device, and converts the digital signal sent by the network device into an analog signal. The phone line goes out.

（3）Sharing is not recommended. The method of choosing a network cable and a telephone line to share a network cable is common in the network systems of small and medium-sized enterprises, especially small enterprises. Some network managers have neutralized the telephone and network for the consideration of saving the funds of the integrated wiring for the enterprise, and chose the method of sharing the same network cable with the network cable as the solution to the current situation. In order to avoid later management, maintenance and troubleshooting considerations, it is not recommended that the telephone and the network share a network cable.

3、Enterprise networking is to choose the super five or six network cable

There is no difference between the use of Category 5 and Category 6 networks, and the connection scenarios and costs used are different.

The recognition is “CAT6”, attracting 250M, Category 6 unshielded twisted pair can support Ethernet implementation very well, and the transmission distance of 100m is upgraded. Six types of functional systems are widely used in the design of sub-machine rooms and floors that retain the six types of non-intrusive capabilities. Category 6 non-intrusive twisted pair cables are expensive, but because they have very good advantages over Category 5 systems and can support 1000Base-T very well, they have slowly become the new favorite of integrated pets.

If you consider the future application requirements of the network, theoretically the most advanced wiring products should be installed, because it is often difficult to update and replace after the installation of cables. Basically, a wiring system must be used as a standard for at least 10 years and can support 4 to 5 generations of networks The performance of the equipment is updated, if the future network equipment needs better cables to increase the data speed. So, it is inevitable to use Category 6 cables to replace Category 5e cables.

However, these cable re-assembly projects are very expensive, so even if the price of Category 6 products is slightly more expensive than Category 5 products, in order to reduce future network upgrade problems, Category 6 products are still worth considering.

 

 

Hello, everyone, welcome to Jiexi Kunlian Cable Co.,Ltd , in this article,we are going to discuss the difference between Fiber broadband and ordinary broadband.

Chapter 1: The difference between optical fiber dedicated line and ordinary broadband   There are dedicated line access and broadband dial-up access commonly used to access the Internet, so what is the difference between dedicated line and ordinary broadband? Here’s an answer for everyone.  Fiber Internet access (dedicated line access) and ordinary broadband Internet access (adsl) are two different Internet access methods. The biggest difference between the two is the difference in transmission media. Fiber Internet access (dedicated line access) Optical signal transmission, and ordinary broadband, that is, adsl Internet access completes the transmission of electrical signals, so the speed of optical fiber Internet access will be much faster than ordinary broadband Internet access.
1.Optical fiber Internet access (dedicated line access) has a fixed ip but ordinary broadband (adsl) does not have a fixed ip, which is what we usually call the public network ip. It is unique in the world, and it can be bound to the enterprise server as The unique identifier of the server that is accessed by the outside world. And with a fixed ip, our network will be more stable, and there is no need to drop the connection twice in three days like ordinary broadband (adsl)

2. Optical fiber Internet access (dedicated line access) is dual-channel, while ordinary broadband (adsl) is one-way. Usually, the process of surfing the Internet involves two aspects of broadband, the network uplink and the network downlink. If you use ordinary broadband (adsl) when uploading files, the download will also be affected. This is determined by the one-way nature of ordinary broadband (adsl). The advantage of fiber-optic Internet access (dedicated line access) is that you are uploading or downloading The other party will not be affected, even if the upload bandwidth is full and the download will not be affected.
Optical fiber Internet access (dedicated line access) has symmetrical uplink and downlink, while ordinary broadband (adsl) uplink is only 512k  If it is 5m optical fiber Internet, ideally its uplink and downlink bandwidth can be full and reach 5m at the same time, while ordinary broadband (adsl) upload is only 512k Maximum bandwidth, and if the upload occupies the bandwidth, its downstream will also be affected, or even drag down the entire network.
4.The access levels of optical fiber Internet (dedicated line access) and ordinary broadband (adsl) are different. Different access levels in the network hierarchy determine the differences in nodes, speed and stability. 5. Optical fiber Internet access (dedicated line access) is an exclusive access method and ordinary broadband (adsl) is a shared access method  This determines that ordinary broadband (adsl) will be affected by the peak period of Internet access and fiber Internet access will not. So, if companies or individuals have special requirements for the stability, security and speed of the website, they still have to choose a dedicated line for access.

Chapter 2: What is the main difference between optical fiber and broadband  What is the main difference between optical fiber and broadband? Browsing times: 5342 times Reward points: 0 | Resolution time: 2009-9-5 13:48 |  Questioner: 8227786 Best Fiber Internet access is the real broadband Internet access. The key to Internet access depends on the Internet connection method. At present, the main ones are: 1. ADSL broadband is used to use the existing telephone line at home, and then install an ADSL modem (also called a cat modem), the Internet speed is about 2Mb/s, which is currently the main Home internet access.
2. Community broadband: generally use optical fiber to connect to the community, and then connect to users through switches and network cables, so that everyone can share the Internet, as is the case with multiple computers in Internet cafes. The speed is optional, generally 10Mb/s, 100Mb/s, or even 1000M, etc. This is also the case in universities. Of course, the backbone of all networks uses optical fiber to transmit data.
2.Wireless Internet access: It is divided into two types: wireless LAN and true wireless Internet access. Wireless LAN: A wireless router is added to the above two Internet access methods. After setting up, you can use its wireless LAN network card to access the Internet, and it can only be effective within a range of tens of meters near the router (similar to PHS). The real wireless online is to use the existing mobile phone wireless network, such as the current 3G network, and the notebook opens the Internet service through the wireless Internet network card and the mobile phone card. The speed is around 3Mb/s. The download speed B/s, that is, bytes/second is 8 times of b/s (bits/second).

Chapter 3: The difference between optical fiber and ordinary network cable  What is the difference between optical fiber and ordinary network cable? What is the difference between optical fiber and ordinary network cable? The network transmission medium in network hardware is usually called network cable. At present, the more common network cables are divided into thin coaxial cables, thick coaxial cables, twisted pairs and optical fibers.
Comparison of optical fiber and ordinary network cable:  1. Coaxial cable  Coaxial cable is a type of transmission medium that many friends are familiar with. It is a cable with a central copper conductor wrapped in layers of insulated wires. Its biggest feature is anti-interference It has good ability, stable data transmission, and cheap price, so it was once widely used, such as closed-circuit television lines. However, coaxial cables used more in the past, mainly because the cost of the bus structure network composed of coaxial cables is lower, but the damage of a single cable may cause the entire network to be paralyzed and maintenance is difficult. This is its biggest drawback. Coaxial cables in Ethernet applications are mainly divided into thick coaxial cables (10Base5) and thin coaxial cables (10Base2). The thick coaxial cable is not used much now, and there is still some market for the thin coaxial cable. Thin coaxial cables are generally sold at a few yuan per meter in the market, which is not too expensive. In addition, the coaxial cable is used to connect with the BNC head. The coaxial cable sold on the market is generally the finished product that has been connected with the BNC head. You can directly choose it.

3.Twisted pair product recommendation: Super Category 5 twisted pair  Twisted pair is a flexible communication cable that contains pairs of insulated copper wires. It is characterized by low price, so it is widely used, such as our common Telephone line etc. According to the difference of the maximum transmission rate, twisted pair can be divided into 3 types, 5 types and super 5 types. The rate of category 3 twisted pair is 10Mb/s, category 5 can reach 100Mb/s, and category 5 can be as high as 155Mb/s, which can meet the needs of future multimedia data transmission, so it is recommended to use category 5 or even category 5 double Stranded wire. Twisted pair can also be divided into shielded twisted pair (STP) and unshielded twisted pair (UTP). STP twisted pair cable has a lower speed (only 4Mb/s), but its anti-interference performance is stronger than UTP twisted pair cable, so the price is much more expensive. Now this kind of twisted pair cable is a few yuan per meter cheaper. In contrast, UTP twisted pair is relatively inexpensive. In addition, the popular names of commonly used 10M and 100M unshielded twisted pairs are 10Base-T and 100Base-T, which you can often see on the market. The RJ45 crystal plug is used in conjunction with the twisted pair cable, which is used to make the joint between the twisted pair cable and the RJ45 interface of the network card. The quality of it is directly related to the stability of the entire network and cannot be ignored.

4.Optical fiber   Optical fiber is a new generation of transmission media. Compared with copper media, optical fiber has greatly improved in terms of safety, reliability and network performance. In addition, the bandwidth of optical fiber transmission greatly exceeds that of copper cables, and the maximum connection distance supported by it is more than two kilometers, which is an inevitable choice for building a larger-scale network. Because optical fiber has the advantages of good anti-electromagnetic interference, strong confidentiality, fast speed, large transmission capacity, etc., its price is also relatively expensive, and it is rarely used in household occasions. There are currently two different types of optical fibers that are more common, namely single-mode optical fibers and multi-mode optical fibers (the so-called “mode” refers to a beam of light entering the optical fiber at a certain angle). Multimode fiber is generally used for network connection in the same office building or in a relatively close area. The single-mode optical fiber transmits data with higher quality and longer transmission distance, and is usually used to connect office buildings or geographically dispersed networks. If optical fiber is used as the network transmission medium, it is necessary to add optical transceivers and other equipment, so the cost is greater. However, the optical fiber has greatly improved in terms of safety, reliability and network performance. To sum up, the material and price of optical fiber and ordinary network cable are different.

Hello, welcome to Jiexi Kunlian Cable Co.,Ltd,  in this article, we will discuss the wiring difference between Cat6 and Cat7.

Wiring installation difference between Cat6 and Cat7

With the development of the information age, people’s needs are also increasing. In the integrated wiring industry, there is a certain gap between Category 6 network cables, Category 7 network cables and optical fibers. Judging from the current consumption market level of the domestic cabling industry, for a long period of time, Category 7 network cables still meet people’s demand for bandwidth. However, as data center technology and optical fiber supporting equipment are updated and upgraded, the competition between Category 6 and Category 7 network cables and optical fibers will continue to escalate. Below we analyze the six categories and seven categories.

 

Category 6 cable:

The transmission frequency of Category 6 cable is 1MHz～250MHz. The comprehensive attenuation crosstalk ratio (PS-ACR) of Category 6 wiring system should have a larger margin at 200MHz, which provides twice the bandwidth of Category 5 . The transmission performance of Category 6 cabling is much higher than that of the Super Category 5 standard, and is most suitable for applications with a transmission rate higher than 1Gbps. An important difference between Category 6 and Category 5 is that it improves the performance in terms of crosstalk and return loss. For a new generation of full-duplex high-speed network applications, excellent return loss performance is extremely important. The basic link model is cancelled in the six types of standards. The wiring standard adopts a star topology. The required wiring distance is: the length of the permanent link cannot exceed 90m, and the channel length cannot exceed 100m. In June 2002, the ANSI/TIA/EIA568-B copper twisted pair category 6 standard was officially released.

Cat7 wiring installation:

the latest twisted pair in the ISO/IEC 11801 Category 7/F level standard, which is mainly used to adapt to the application and development of 10 Gigabit Ethernet technology. But it is no longer an unshielded twisted pair, but a shielded twisted pair. 4 pairs of core diameter 23AWG single strands of high-quality oxygen-free copper are used as conductors (the copper conductor is insulated with FMPE material), the wire pair and the cable are integrated with aluminum foil and the high-efficiency double shielding structure, the cross is isolated, and the transmission frequency is also extended to 600MHz. Category 7 network cable is an 8-core shielded cable, each pair has a shielding layer (usually a metal foil shielded Foil Shield), and then there is a shielding layer outside the 8 cores (usually a metal braided wire mesh shielded Braided Shield), The interface is the same as the current RJ-45.

Different utilization environment

Category 6 wiring: most suitable for applications with a transmission rate higher than 1Gbps.

Category 7 wiring: It can provide at least 500MHZ comprehensive attenuation to crosstalk ratio and 600MHZ overall bandwidth.

Different performance

Category 6 wiring: It can be used for voice, integrated service data network (ISDN), ATM155Mbps and 622Mbps, 100MbpsTPDDI, fast Ethernet and Gigabit Ethernet; it has longer transmission distance, less transmission loss, wear resistance, and pressure resistance than Category 5 And other characteristics.

Category 7 : The latest twisted pair in the ISO/IEC 11801 Category 7/F level standard. It is mainly used to adapt to the application and development of 10 Gigabit Ethernet technology. But it is no longer an unshielded twisted pair, but a shielded twisted pair, so it can provide at least 500MHZ comprehensive attenuation to crosstalk ratio and an overall bandwidth of 600MHZ, it is a Category 6 wire and a Super Category 6 wire The transmission rate can reach 10Gbps.

The choice of cable type should be comprehensively considered in terms of cable use, required transmission capacity, transmission bandwidth, and price. There are three types of cables: unshielded twisted pair, shielded twisted pair, and optical cable.

1. Category 6 unshielded twisted pair UTP is currently the most widely used wiring system in China. It is suitable for network applications with a transmission bandwidth below 250MHz and no special performance requirements. Its advantages are good overall performance, low price, and comparison of construction and maintenance. convenient. Category 6 wiring system has reached the performance limit of unshielded twisted pair.
2. The aluminum foil shielded twisted pair FTP has a large bandwidth, strong anti-interference performance, and has the characteristics of low smoke and halogen free. In contrast, shielded cables are higher in price and installation cost than unshielded cables, and cable bending performance is slightly worse. Category 6 lines and previous shielding systems mostly use this form.

 

4. Independently shielded twisted pair STP, each pair of wires has an aluminum foil shielding layer, and the four pairs of wires together also have a common metal braided shielding layer. This is the standard structure of the seven types of wires. It is suitable for high-speed network applications, provides highly confidential transmission, supports future new applications, and helps to unify the wiring platform of current network applications, so that all kinds of information from e-mail to multimedia video can be in the same high-speed system In the transmission

The additional shielding layer makes the Category 7 wiring have a larger wire diameter. These characteristics require special care when designing the installation routing and termination space, leaving a lot of space and a larger bending radius. At present, our company cable The SUOER series of integrated wiring products have been launched in the 7 types of wiring systems, and all performances have passed the inspection and reached the standard, in line with international standards.

 

Hello, welcome to Zhuhai hanqin cable co.,ltd

In this article, we will discuss the difference between Cat5e and Cat6.

At present, the twisted-pair cables commonly used in local area networks are generally unshielded, Category 5, 4-pair (ie, 8 wires) cables. The transmission rate of these twisted pairs can reach 100Mbps.

The outer protective rubber of category 3 twisted pair on the market is thin, the rubber is marked with “CAT3”, and the outer carton is marked with “category 3”, the price is lower; the outer protective rubber of category 5 twisted pair is thick , The rubber is marked with “CAT5”, and the outer carton is marked with “Category 5”, the price is higher. When buying, do not buy low-quality Category 5 twisted-pair cables for cheap. These products can often only be used as Category 3 twisted-pair cables.

Super Category 5 twisted pair is an unshielded twisted pair. Compared with the ordinary category 5 twisted pair, the super category 5 twisted pair has smaller attenuation and stronger anti-interference ability when transmitting signals. In a 100M network, the interference level of user equipment is only 1/4 of that of ordinary Category 5 lines, which is an ideal solution for network applications.

“Category 5” refers to category 5 unshielded twisted pair (UTP—Unshielded Twisted Pair)

The unshielded twisted pair cable is composed of multiple twisted pairs and a plastic sheath. Category five refers to the five different quality levels defined by the International Electrical Industry Association for twisted-pair cables.

Category 5e unshielded twisted-pair cable is a cable that has improved some of the performance of the existing Category 5 shielded twisted-pair cable. Many performance parameters, such as near-end crosstalk, attenuation crosstalk ratio, return loss, etc. Improved, but its transmission bandwidth is still 100MHz.

Category 5 twisted-pair cable also uses 4 winding pairs and 1 tensile wire. The color of the pair is exactly the same as that of Category 5 twisted-pair cable. They are white orange, orange, white green, green, white blue, blue, and white. Brown and brown. The diameter of bare copper wire is 0.51mm (wire gauge is 24AWG), the diameter of insulated wire is 0.92mm, and the diameter of UTP cable is 5mm.

Category 5e twisted pair cables are usually only used for 100Mb/s fast Ethernet to connect desktop switches to computers. If you want to upgrade the network to Gigabit Ethernet in the future, you may wish to use Category 5e unshielded twisted pair in the horizontal wiring. Category 5e unshielded twisted pair can also provide up to 1000Mb/s transmission bandwidth, but it often requires the support of expensive special equipment.

The parameters of the six types of unshielded twisted pairs have been greatly improved, and the bandwidth has also been extended to 250MHz or higher. Category 6 twisted-pair cables are different from Category 5 or Category 5 twisted-pair cables in appearance and structure. Not only does the insulated cross frame increase, but the four pairs of twisted-pair cables are placed on the fourth of the cross frame. Within a groove, and the diameter of the cable is thicker.

The cross frame in the center of the cable rotates with the change in length, and the four pairs of twisted pairs are clamped in the groove of the frame to maintain the relative position of the four pairs of twisted pairs to improve the balance characteristics and crosstalk attenuation of the cable. In addition, ensure that the balance structure of the cable is not damaged during the installation process. The diameter of the bare copper wire of Category 6 unshielded twisted pair is 0.57mm (the wire gauge is 23AWG), the diameter of the insulated wire is 1.02mm, and the diameter of the UTP cable is 6.53mm.

According to the different electrical properties, twisted pair wires can be divided into three types, five types, super five types, six types and seven types of twisted pairs. The prices of different types of twisted-pair cables vary greatly or even widely, and the scope of application is also very different. Except that the traditional voice system still uses Category 3 twisted pair, network cabling is currently basically using Category 5 or Category 6 unshielded twisted pair. Although Category 5 unshielded twisted pair cables can still support 1000Base-T, they have gradually faded out of the cabling market because they are almost the same in price as Category 5 unshielded twisted pairs.
Although the price of Category 6 unshielded twisted pair cable is relatively high, it is slowly becoming the new favorite of integrated wiring because it has very good compatibility with the Category 5 cabling system and can support 1000Base-T very well. CAT7 shielded twisted pair is a brand-new wiring system. Although it has excellent performance, it is expensive. The construction is complicated and there are fewer products to choose from, so it is rarely used in wiring projects.
Category 6 unshielded twisted pair can support Gigabit Ethernet very well and achieve a transmission distance of 100m. Therefore, the Category 6 cabling system is widely used in the cabling of the sub-server room and the horizontal cabling that retains the ability to upgrade to Gigabit Ethernet. According to the international cabling standard ISO11801, the life expectancy of a cabling system is at least 10 years. As a long-term basic investment, integrated cabling should fully consider the potential needs of the network and the development of the cabling system. Therefore, it is recommended to choose six types of products to build the cabling system under the conditions of capital permitting.
If you consider the future application requirements of the network, theoretically the most advanced wiring products should be installed, because it is often difficult to update and replace after the installation of cables. Basically, a wiring system must be used as a standard for at least 10 years and can support 4 to 5 generations of networks The performance of the equipment is updated, if the future network equipment needs a better cable to increase the data speed.
So, it is inevitable to use Category 6 cables to replace Category 5e cables, but these cables are very expensive to rebuild, so even if the price of Category 6 products is slightly more expensive than Category 5 products, in order to reduce future network upgrade problems, Six types of products are still worth considering.

Difference between cat5e and cat6

The logo of Category 5 cable is “CAT5”, with a bandwidth of 100M, which is suitable for networks below 100M; the logo of Category 5 Super Cable is “CAT5E”, with a bandwidth of 155M, which is the current mainstream product; the logo of Category 6 cable is “CAT6” , Bandwidth 250M, used to set up a gigabit network, is the trend of future development.

“Category 5” refers to Category 5 Unshielded Twisted Pair (UTP—Unshielded Twisted Pair)

The unshielded twisted pair cable is composed of multiple twisted pairs and a plastic sheath. Category five refers to the five different quality levels defined by the International Electrical Industry Association for twisted pair cables.

Category 5e unshielded twisted-pair cable is a cable that has improved some of the performance of the existing Category 5 shielded twisted-pair cable. Many performance parameters, such as near-end crosstalk, attenuation crosstalk ratio, return loss, etc. Improved, but its transmission bandwidth is still 100MHz.

Category 5 twisted-pair cable also uses 4 winding pairs and 1 tensile wire. The color of the pair is exactly the same as that of Category 5 twisted-pair cable. They are white orange, orange, white green, green, white blue, blue, and white. Brown and brown. The diameter of bare copper wire is 0.51mm (wire gauge is 24AWG), the diameter of insulated wire is 0.92mm, and the diameter of UTP cable is 5mm.

Although CAT5e unshielded twisted pair can also provide up to 1000Mb/s transmission bandwidth, it often requires the support of expensive special equipment. Therefore, it is usually only used in 100Mb/s fast Ethernet to connect desktop switches to computers. If you are not going to upgrade the network to Gigabit Ethernet in the future, you may wish to use Category 5e unshielded twisted pair in the horizontal cabling.

“Category 6” refers to category 6 unshielded twisted pair 

The parameters of the six types of unshielded twisted pairs have been greatly improved, and the bandwidth has also been extended to 250MHz or higher. Category 6 twisted-pair cables are different from Category 5 or Category 5 twisted-pair cables in appearance and structure. Not only does the insulated cross frame increase, but the four pairs of twisted-pair cables are placed on the fourth of the cross frame. Within a groove, and the diameter of the cable is thicker.

The cross frame in the center of the cable rotates with the change in length, and the four pairs of twisted pairs are clamped in the groove of the frame to maintain the relative position of the four pairs of twisted pairs to improve the balance characteristics and crosstalk attenuation of the cable. In addition, ensure that the balance structure of the cable is not damaged during the installation process. The diameter of the bare copper wire of Category 6 unshielded twisted pair is 0.57mm (the wire gauge is 23AWG), the diameter of the insulated wire is 1.02mm, and the diameter of the UTP cable is 6.53mm.

Category 5 or Category 6?

According to the different electrical properties, twisted pair wires can be divided into three types, five types, super five types, six types and seven types of twisted pairs. The prices of different types of twisted-pair cables vary greatly or even widely, and the scope of application is also very different.

Except that the traditional voice system still uses Category 3 twisted pair, network cabling is currently basically using Category 5 or Category 6 unshielded twisted pair. Although Category 5 unshielded twisted pair cables can still support 1000Base-T, they have gradually faded out of the cabling market because they are almost the same in price as Category 5 unshielded twisted pairs.

Although the price of Category 6 unshielded twisted pair cable is relatively high, it is slowly becoming the new favorite of integrated wiring because it has very good compatibility with the Category 5 cabling system and can support 1000Base-T very well. CAT7 shielded twisted pair is a brand-new wiring system. Although it has excellent performance, it is expensive. The construction is complicated and there are fewer products to choose from, so it is rarely used in wiring projects.

Category 6 unshielded twisted pair can support Gigabit Ethernet very well and achieve a transmission distance of 100m. Therefore, the Category 6 wiring system is widely used in the wiring of the sub-server computer room, and the horizontal wiring that retains the ability to upgrade to Gigabit Ethernet. According to the international cabling standard ISO 11801, the life expectancy of a cabling system is at least 10 years. As a long-term basic investment, integrated cabling should fully consider the potential needs of the network and the development of the cabling system. Therefore, it is recommended to choose six types of products to build the cabling system under the conditions of capital permitting.

If you consider the future application requirements of the network, theoretically the most advanced wiring products should be installed, because it is often difficult to update and replace after the installation of cables. Basically, a wiring system must be used as a standard for at least 10 years and can support 4 to 5 generations of networks The performance of the equipment is updated, if the future network equipment needs a better cable to increase the data speed.

So, it is inevitable to use Category 6 cables to replace Category 5e cables, but these cables are very expensive to rebuild, so even if the price of Category 6 products is slightly more expensive than Category 5 products, in order to reduce future network upgrade problems, Six types of products are still worth considering.

Super Category Six”

Belden IBDN has developed a high-performance cabling system that can operate normally above 40℃, and officially launched the IBDN 4800LX system at the end of 1999. Its final index reaches 300MHz bandwidth, and it can still reach the 20 specified in the category 6 standard at 50℃. ℃ performance index. In order to distinguish it from the ordinary Category 6 wiring system, this kind of wiring with bandwidth performance far exceeding Category 6 is called Category 6 Super.

Most of the Super Category 6 definitions use the same modules and jumpers as Category 6 of the same brand, so the main difference between them is in the data. IBDN’s Super Category 6 data 4800LX has been operating normally at the operating temperature from the beginning, so its features include a large wire diameter. The transmission diameter has been increased from 0.5mm (24AWG) for ordinary Category 6 to 0.6mm (23AWG). ; Some manufacturers used 24AWG in the initial Super-6 data and tried their best to improve the NEXT method, but the improvement details in 2002 increased the wire diameter to 23AWG. The other is a cross-shaped pair call bar added between the 4 twisted pairs. Without the cross notification, the data line of the smartphone may have a serious impact between the lines in another message between the line and the line, which may cause a sudden crosstalk problem. 4800LX is a super 6-category decoration with scattered cross stitch strips, which reduces its performance during installation. Later digital groups followed suit and adopted similar techniques.