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When does an integrated cabling call for a shielded cabling system?(I)

  • 2018-04-08
Before we know when to use the shielded cabling system in the integrated cabling project, we should first have a clear understanding of the shielded wiring system. Here is the purpose of the shielded cabling system.
1.Purpose of shielded wiring system
The shielding system is designed to ensure the transmission performance of the cabling system in the presence of EMI. The anti-jamming capability should include two aspects: the ability to resist the external electromagnetic interference and the ability of the system itself to radiate the electromagnetic interference. For the latter, Europe has adopted the EMC standard for electromagnetic compatibility testing, while for the former, there is no quantitative standard for shielding in the case of how much V / M (unit of electromagnetic strength) of the external electromagnetic field should be achieved. Although theoretically, a metal shield layer on the surface of cables and connectors can effectively filter out unnecessary electromagnetic waves (this is also the method used in most current shielding systems).
It is necessary to determine whether a shielded or non-shielded wiring system should be built according to the specific circumstances. Given the following factors, units requiring the high-level confidentiality, like units related public security and banking, can build shielded LAN.
(1) Interference.  Cables and equipment often interfere with other components or are affected by other sources of interference, thus disrupting the transmission of data and, in serious cases, leading to complete paralysis of the entire system. According to the PREN50174, some of the main sources of interference are as follows:
1)Power distribution .
2)fluorescent lighting.
3)Radio transmission equipment ( such as Wireless telephone, radio station, television set)
4)utp to utp cable.
5)Office equipment (like photocopiers, printers, computers, paper shredders)
7)Industrial machinery (engine, etc.)
Cable twisting can only protect the cable from the magnetic field, but not from the electric field. However, many interference sources emit electric or electromagnetic fields (radiation fields), so only shielding can protect the network from all interference sources.
(2)  eavesdropping
1)Potential eavesdroppers, cheaters and programmers are on the rise. They can intercept information transmitted on UTP cables, causing serious damage and loss. The shielding network with shielded cables and components can obviously reduce the emission level of electromagnetic waves in the surrounding environment.
2)If there is no physical connection, it is easy to intercept the information transmitted on the UTP cable when it is used only as a transmission antenna. The shielded twisted pair (STP) is difficult to intercept because of its low scattering. In most unprotected states, eavesdroppers only need a radar receiver, an electronic signal generator and a portable computer to intercept data within a few hundred meters.
Please stay tuned.
This article comes from Jiangsu Hansheng Cable Technology Co., Ltd., Please reprint with the source indicated! 
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