What is the difference between twisted pair and fiber optics in surveillance

Twisted pair and signal transmission through differential current, but with the increase of data volume, if the rate exceeds 100Mbps, the attenuation of twisted pair will become larger and larger, in other words, if you want to carry out data transmission of more than 1km of 500Mbps, twisted pair is not competent, and you must use optical fiber for communication;

Optical fiber can theoretically transmit thousands of gig of data, but because the current technology has not yet developed such a high-bandwidth laser module, so the current maximum is 10G Ethernet optical transmission, optical fiber theory can transmit infinite distance, as long as the emitted optical power is enough, there is no problem with transmission around the earth, but generally not so used, the farthest transmission 100-200km is available, but the middle needs to increase the optical repeater, because of the reason of optical dispersion, the transmission distance of light in the optical fiber is too large, It will affect the sensitivity of the reception, so that the sensitivity of the reception is reduced, so between 100-200km will add a fiber optic repeater;

Fiber splicing refers to the re-splice of an optical fiber after it has been disconnected; The composition of the optical fiber is silica, which is not like the cable we use daily, and the composition of the cable is pure copper, so it is also called copper; If the copper ladle is disconnected, it can be soldered or screwed together, but if the optical fiber is disconnected, then it must be welded;

Optical fiber fusion splicing requires a light fusion splicer, because optical fiber is made of silica, so the characteristics are similar to glass; The optical fusion splicer uses a laser to produce a high temperature of several thousand degrees in an instant, melts the two broken optical fibers, and fuses them together, which is optical fusion splicing;

There is no difference in the application, and the consideration of twisted pair or optical fiber in engineering construction is mainly based on the length of the line to determine the use of twisted pair or optical fiber. After all, the cost of optical fiber is still relatively expensive.

The transmission signal mode is different, the twisted pair transmits the differential electrical signal, and the optical fiber transmits the serial optical signal.

Twisted pair cables are used to transmit electrical signals, while optical fibers are used to transmit optical signals.

Twisted pair (TP) is the most commonly used transmission medium in integrated wiring engineering, which is composed of two copper wires with an insulating protective layer. Two insulated copper wires are twisted together according to a certain density, and the radio waves radiated by each wire in the transmission will be canceled by the radio waves emitted by the other wire, effectively reducing the degree of signal interference.

Twisted pair wire is generally made of two 22 26 gauge insulated copper wires wound with each other, from which the name "twisted pair" comes from. In practice, twisted pair wires are made up of multiple pairs of twisted pairs wrapped together in an insulated cable sleeve. If one or more pairs of twisted pair cables are placed in an insulating sleeve, they become twisted pair cables [1], but in daily life, "twisted pair cables" are generally directly referred to as "twisted pairs".

Optical fiber is an abbreviation for optical fiber, which is a fiber made of glass or plastic that acts as a light conduction tool. The principle of transmission is 'total reflection of light'.

Advantages: optical fiber has many advantages such as wide transmission bandwidth, large capacity, no electromagnetic interference, and little influence by the external environment, and a fiber can transmit all the signals needed in the monitoring system, and the transmission distance can reach hundreds of kilometers.

Disadvantages: The use of optical fiber and optical transceiver requires certain professional knowledge and special equipment, which brings certain difficulties to engineering construction and user use. In addition, for short-distance, small-scale monitoring systems, the use of optical fiber transmission is not economical enough.

1. The difference in function.

The line is the network cable that is mainly transmitted by the network signal, and the analog signal converted by the twisted pair transmitter; We can see surveillance cameras in the community, in the office building where we work, at the entrance of the street, etc., of course, with the monitoring line behind. The network cable is used to connect the local area network, such as our common ** line. It is used to connect to the RJ45 head.

2. The difference on **.

The characteristics of network cables are cheap, and the common network cables in the LAN mainly include twisted pairs, coaxial cables, and optical cables. A twisted pair is a data transmission line that consists of many pairs of wires. **line** is slightly higher than the network cable.

3. The difference in the distance of passing and fighting.

The network cable cannot transmit more than 100m of network signal. Twisted pair: When the horizontal cable is used as a data transmission, the permanent link does not exceed 90 meters, and the channel does not exceed 100 meters.

Coaxial cable: 75-7 coaxial cable is about 200-250 meters, 75-5 is about 100-150 meters.

**Line transmission analog signal, taking 75-5 as an example, the transmission distance can reach 800M without interference, the transmission SDI signal requirements are relatively high, and there can be a joint transmission of about 120M in the middle.

4. The method of using the line is different.

Advantages and disadvantages of both lines:

The wire must have a good shielding effect, and the role of the braid layer is here, the shielding layer can well shield the external interference magnetic field, and provide a good protection environment for the transmission of the core signal.

2. Coaxial cable.

It can support high-bandwidth communication on relatively long repeater-less lines, and the diameter of thin cables is 3 8 inches thick, which takes up a lot of space in the cable duct; Cannot withstand tangles, pressure, and severe bending. <>

First of all, let's talk about the twisted pair, the twisted pair is stranded every two pairs of lines, which can effectively resist the envy noise. This kind of line is cheap, and it is very convenient to access the wiring.

The coaxial ** is higher than that of the twisted pair, and the transmission rate is also higher.

Fiber is the highest. Optical fibers are also divided into multi-membrane fibers and single-membrane fibers, and in comparison, single-membrane fibers are the fastest.

Wireless network is suitable for many places, and the application in LAN is mainly suitable for some office buildings to do wireless coverage or information transmission between two adjacent buildings.

Twisted pair and optical fiber are both a kind of network cable, among which, optical fiber has a high cost, but has the advantages of long transmission distance and signal is not easy to be interfered with; Twisted pair cables are divided into shielded twisted pair and unshielded twisted pair according to type, and according to the transmission rate, they are divided into 3 categories, 4 types, 5 types, super 5 types, 6 types and so on.

In addition, there are also coaxial cables for network connections.

The main differences between the three are as follows: 1. Twisted pair 1It has many advantages such as strong anti-interference ability, long transmission distance, easy wiring, and low cost.

2.Because there is also a large attenuation of the twisted pair signal, the frequency of the signal cannot be too high when the transmission distance is long, while high-speed signals such as Ethernet can only be limited to less than 100m. 3.

For the first signal, the bandwidth reaches 6MHz, if it is transmitted directly in the twisted pair, it will also attenuate greatly, so the signal must be amplified and compensated to achieve long-distance transmission on the twisted pair, and the twisted pair transmission equipment is to complete this function. 4.Twisted pair and twisted pair transmission equipment are very cheap, not only do not increase the cost of the system, but when the distance increases, its cost decreases a lot compared with coaxial cable.

Therefore, the transmission of twisted pair cables in the monitoring system has obvious advantages. 2. Optical fiber 1Optical fibers transmit signals in the form of light pulses, so the material is also glass or plexiglass.

It consists of a fiber core, a cladding, and a protective cover. 2.The structure of the optical fiber is very similar to that of the coaxial cable, the center is an optical fiber made of glass or transparent plastic, and the protective material is wrapped around the slag stove, and multiple optical fibers can be combined in one optical cable as needed.

1. The nature is different: full-duplex transmission refers to the fact that the cross-punch pants replacement machine can also receive the data and macro data while sending the data scatter simplification, and the two are carried out synchronously, and the current switches support full duplex. There is only one action in a period of time, for example, a narrow road in a day, only one car can pass at the same time, when there are currently two cars crossing, in this case, only one car can cross first, and wait until the other car is the first to drive.

2. Different speeds: In full-duplex mode, the maximum speed of the network cable can reach more than 100 megabytes, and in the half-duplex mode, the speed that the network cable can achieve is usually about 10 megabytes. 3. Different modes:

The network cable of the full-duplex mode can work in both full-duplex mode and semi-double-duplex mode; However, the network cable in half-duplex mode cannot work in full-duplex mode.

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