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Twisted pair: Twisted pair is divided into shielded (Shielded Twisted pair, referred to as STP) and unshielded (Unshielded Twisted pair, referred to as UTP). The so-called shielding means that the signal wire inside the network cable is wrapped with a layer of metal mesh, and the shielding layer is the insulating sheath, which can effectively isolate the interference of external electromagnetic signals.

UTP is currently the most frequently used network cable in local area networks. This kind of network cable is wrapped in a plastic insulating sheath with 8 signal wires. Two of them are entangled with each other as a pair, forming a total of four pairs. The twisted pair is also named. The purpose of twisted pairs twisted with each other is to use the electromagnetic field generated by the current in the copper wire to cancel the interference of adjacent lines and reduce the interference from the outside world. The number of times that each pair of wires are twisted with each other in each inch of length determines the anti-interference ability and the quality of communication. The tighter the twist, the higher the communication quality and the higher the network data transmission rate. Of course, its cost is also higher. high.

Coaxial cable: Coaxial cable refers to a cable with two concentric conductors, and the conductor and the shielding layer share the same axis. Because it wraps the insulating material outside the main line, and there is a layer of woven shielded metal wire outside the insulating material, it can well block the external electromagnetic interference and improve the quality of communication. The advantage of coaxial cable is that it can support high-bandwidth communication on a relatively long line without repeater, but its disadvantages are also obvious: First, it is large in size, and the diameter of a thin cable is 3/8 inches thick, which takes up the cable. There is a lot of space in the pipeline; the second is that it cannot withstand tangles, pressures and severe bends, which will damage the cable structure and prevent signal transmission; and the third is the high cost. All these shortcomings can be overcome by twisted-pair cables. Therefore, in the current local area network environment, they have basically been replaced by Ethernet physical layer specifications based on twisted-pair cables. Coaxial cables are divided into thin cables and thick cables.

The popularity of computers and the rapid development of technology have eliminated many computer peripherals; the connection methods of computer peripherals are also diverse, from the early PS2 interface that supports the keyboard and mouse and the 25-pin large parallel port transmission line of the old printer to the present HDMI video cable, with the update of the equipment, there will be more peripheral cables with different interfaces in the future; today I will lead you to review the standard cables of computer peripheral peripherals.

AV video cable; In the DVD era, this is a new generation of transmission cable upgraded from RF cable, which separates the transmission of sound and image for the first time; AV cables are still widely used by everyone. AV audio cable; mainly used to connect the computer to the power amplifier equipment, and input audio from the computer to the audio equipment.

The COM port cable (also known as R232) is mainly used to connect older computer peripherals; for example, printer R232 to USB: It is mainly used to convert some devices because they are too old to be supported by the computer. For example, old-fashioned printers, current computer motherboards do not support the COM interface, and the old device can continue to be used with this cable.

The sweeper refers to the sweeping robot. In the near future, it will become an indispensable cleaning helper for every family like white goods. Products will also develop from primary intelligence to a higher degree of intelligence, gradually replacing manual cleaning.

With the continuous improvement of living standards in China, the sweeping robots that have been sold in the European and American markets have entered the homes of ordinary people and are accepted by more and more people. As the cleaning assistant of the company, the sweeper greatly improves the cleaning efficiency and cleaning effect of the road, but when the sweeper fails, it is more annoying, so is it a problem with the selection of the line?

The general problem with the sweeper is that it does not move. Therefore, the wire we use for the sweeper must pass the quality, and the wire from the master manufacturer is a product that has passed the quality inspection. Check whether the key switch has activated the sweeper and the sweeper’s key. After the switch is turned to the right, if you hear the start of the sweeper, it means that the sweeper has not started just now; if there is no sound after starting the sweeper, the key switch is damaged, or the fuse of the sweeper is blown, so you need to replace the key switch Or replace the fuse. Of course, it may be that the wiring of the key switch is loose or broken. Just replace the wiring or tighten the wiring. The key switch, fuse, and wiring are all OK, and the sweeper still does not work, indicating that the battery is abnormal and the battery cannot supply power. , Check if the electricity meter has electricity, first charge it, if the sweeper can go after charging, it means that the electricity meter is damaged and cannot display the real electricity, and the electricity meter needs to be replaced; if the sweeper still can’t drive, there is a problem with the battery , Replace the battery; the tire is solidified and wrapped around the sweeper and does not drive, but the noise is loud, indicating that the tire is entangled and locked. Forcibly starting the sweeper will cause damage to the engine load and solve the tire entanglement. If it is not the wiring problem, it may be the installation and internal problems of the machine itself. The above questions are for reference only.

The audio cable directly transmits the power signal. Due to the large current, the copper core of the wire is usually thicker. In order to ensure high frequency passage and reduce resistance attenuation, silver-plated, gold-plated or oxygen-free copper wires are mostly used. Audio cables are generally divided into copper-plated audio cables and oxygen-free copper audio cables. Audio cables mainly transmit power signals, so speaker cables are required to have excellent conductivity and high-quality transmission capabilities. The audio cable is also called the speaker cable, which is mainly used to connect the power amplifier and the main speaker, surround speakers in the home theater, that is, to connect the power amplifier and the speakers. Compared with video cables and audio cables, its current signal is relatively large. Due to the large signal amplitude, audio cables often have no shielding layer. For this kind of wire, the key is to reduce its resistance, because the output resistance of modern power amplifiers is very low, so the requirements for speaker wire will also increase, such as the use of large cross-sectional area or multi-stranded wire. At present, oxygen-free copper audio cables, also known as gold and silver cables, are more mainstream and have lower resistance. Audio gold and silver cables usually have no shielding layer, because the current signal flowing through them is larger than that of audio cables and video cables, and the signal amplitude is very large. The most important thing is to reduce the resistance of the line. The impedance at the output of the power amplifier is very low. The audio line passes low-power, low-current signals, and has high impedance and is susceptible to interference. Therefore, it is generally a shielded wire, and the wire is relatively thin. Audio cables usually have a shielding layer, but audio cables often do not have a shielding layer. The key is to reduce resistance. Among the deep blue highway audio cables, the more expensive is the dedicated oxygen-free copper speaker cable, which is mainly characterized by good conductivity and low resistivity.

The audio signal line can be used to connect the line between mobile phones, CD players, MP3 music output signal devices and power amplifiers. Speaker cables are mainly used for various speakers, PA projects, home theater connections, and public space broadcasting systems.