Proper Selection of shielded and unshielded Cables

The challenge of shielded and unshielded cables, and which cables provide the best solution for copper Structured Cabling networks have been around for a long time. Selecting unshielded twisted pair wires (UTP) and tin foil twisted pair wires (FTP) (or the well-known shielded twisted pair wires (ScTP) in the United States) is not an easy decision. In fact, choosing appropriate shielding technologies from various options and ensuring that these technologies are correctly installed and run is far more important than choosing FTP or UTP.
The general conventions around the world are different. UTP cables are typically the most economical option in the UK, most of Europe, the United States, and Asia, and are sufficient to meet most installation requirements. FTP is dominant in Germany and other European countries, including France, Switzerland and Austria.
One of the real problems with installing the system is data integrity. The fundamental goal of the shielding system is to prevent data from being subject to potential electromagnetic interference (EMI), such as industrial facilities and airports and locations where key systems are running, such as military bases and hospitals.
The well-designed and correctly installed FTP cabling network will undoubtedly improve the signal integrity on the unshielded system. However, Molex enterprise cabling network Department reminds users that, in order to work effectively, the Shielding must be properly grounded. In fact, this is not always easy to implement. The shielding system with poor grounding will actually provide worse performance than the unshielded System at the beginning. In the worst case, shielding itself may become a radiation source, generate a current grounding loop, or receive the surrounding radiation, which may cause harmful interference to the phase data cable.
Blocked type
Blocking is divided into several different types. Two or more stranded wires or four cables can be enclosed in a whole shield. In addition, each cable pair can be separately shielded. In addition, these separately shielded cables can or cannot cover the second-layer overall shielding called Metallic Tin foil internal line pairs (PiMF )).
Either way, in order to ensure effectiveness, Shielding must be electronic end-to-end continuous and grounded correctly. It is also important to select an end-to-end solution when selecting a shielded cabling system. Using Hybrid components of different systems may cause problems due to impedance mismatch.
Shielding system costs, including additional installation required, typically 20-30% higher than equivalent UTP solutions.
Standards and rules
EMI or RF interference (RFI) refers to any unwanted signal that adversely affects the operation of the device or system. In Europe, EMC Act 89/336/EEC and its Supplementary Act 92/31/EEC set radiation and anti-interference requirements for electromagnetic radiation. In the United States, the Federal Communications Commission (FCC) imposes similar regulations on any equipment manufactured or sold in the United States.
You can determine the radiation by measuring the intensity of the radiation. The Unit is V/meter, and its general frequency ranges from 30 kHz to 1000 MHz. EMC regulations provide a family of product standards for information technology equipment-EN55022, which specifies testing procedures and acceptable limits for EMI radiation.
Tests prove that the device can continue to operate effectively when there is a corresponding level of EMI, and the anti-interference capability (or sensitivity) of EMI can be determined ). There is no family of anti-interference capability testing standards for IT equipment, so IT is currently included in the EN50082-1 (domestic, commercial and lighting industry) and EN50082-2 (industrial environment) These two general standards. These standards and basic IEC1000-4 series standards are used to test the anti-interference capability of IT devices.
It is not clear how the cabling structure is integrated into this situation. The recommendation by the well-known entity appointed by the PLD for the British Molex enterprise cabling network Department confirms that the SI 2372: 1992 13th clause excluded structured cabling, it is acceptable that EMC assessment is not performed for large installations in buildings. In addition, the cabling system is included in the passive system in the SI 17th rules, so it is not included in the management scope of electromagnetic regulations.
The British electromagnetic compatibility testing laboratory (EMCTLA) claims that wiring products "will not cause electromagnetic interference, and their performance will not be affected by such interference ". Therefore, the CE mark is not required to be displayed on the cabling component. In fact, this is not legal.
For installed IT systems, manufacturers of active devices and system installers shall share secondary responsibilities of electromagnetic compatibility. The final responsibility to ensure compliance with regulatory requirements depends on the system owner.
The Molex enterprise cabling network department has been executing EMC tests on a series of installation projects to collect data and provide better suggestions to end users and installers on EMC and shielding issues. The UTP and FTP solutions can meet the corresponding radiation and anti-interference capability standards if the system correctly installs the typical configurations including the active devices and wiring components.
Development Prospects
A twisted pair cable can offset the positive and negative signals of each half of the coupling line to realize electromagnetic compatibility. In order to work effectively, a good balance must be maintained during the competition.
Vertical balancing of cables is currently the focus of controversy. The European EN50173 standard is considering including this test in the standard. The test method is based on coupling attenuation, but many people think that this method has many defects or even is not enough. Other methods for vertical balancing testing include line injection and antenna technology.
Seven categories of standards currently being proposed in ISO/IEC/SC25 of the International Standards Committee will require PiMF to shield and end to a shield wire. This shielding level is expected to be used to meet the performance requirements of a standard with a specified transmission bandwidth of about MHz. The alternative must not be shielded and provide higher performance than the copper solution, which is of course optical fiber.
Currently, blocking or unblocking is still a complicated issue. The best recommendation for end users is to consult senior network designers every time a new system is installed.