Recognize the role of six types of shielded network cable

Category 6 shielded network cable:

1) One type of line: Mainly used for voice transmission (One type of standard is mainly used for telephone cables before the early eighties), unlike data transmission.

2) Second-category line: The transmission frequency is 1MHZ, which is used for voice transmission and data transmission with a maximum transmission rate of 4Mbps. It is common in old token networks that use the 4MBPS standard token transfer protocol.

3) Category 3: Refers to the cable currently specified in the ANSI and EIA/TIA 568 standards. The transmission frequency of the cable is 16 MHz. The data transmission used for voice transmission and the maximum transmission rate of 10 Mbps is mainly used for 10BASE--T.

4) Category IV: The transmission frequency of this type of cable is 20MHz. The data transmission for voice transmission and the maximum transmission rate of 16Mbps is mainly used for token-based LAN and 10BASE-T/100BASE-T.

5) Category 5 cable: This type of cable increases the winding density and coats a high quality insulating material with a transmission rate of 100MHz for voice transmission and data transmission with a maximum transmission rate of 10Mbps, mainly for 100BASE-T and 10BASE-T network. This is the most commonly used Ethernet cables.

6) Super Category 5: Super Category 5 has small attenuation, low crosstalk, and higher attenuation and crosstalk ratio (ACR) and signal-to-noise ratio (Structural Return Loss), smaller delay error, and very good performance. Greatly improved. Category 5 is mainly used for Gigabit Ethernet (1000 Mbps).

7) Category 6 cable: The transmission frequency of this type of cable is from 1MHz to 250MHz, and the PS-ACR of the Category 6 cabling system should have a large margin. It provides 2 times more than the 5th category. bandwidth. The transmission performance of the six types of cabling is much higher than the super five standard, and is most suitable for applications with a transmission rate higher than 1 Gbps. An important difference between Category 6 and Category 5 is that it improves 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 has been eliminated from 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 length of the channel cannot exceed 100m.

Due to the severe requirements of the shield system for grounding, it is very easy to cause poor grounding, such as too large grounding resistance, unbalanced ground potential, etc., so that a potential difference will occur between two points of the transmission system, and then the current on the metal shield layer will be generated. Causes the shield to be discontinuous and destroys its integrity. At this time, the shield itself has become the largest source of interference, resulting in its performance is far worse than the unshielded system. When shielded wires are transmitted at high frequencies, they need to be grounded at both ends, which makes it more likely that a potential difference will occur across the shield. It can be seen that the requirements of the shielding system itself constitute the biggest obstacle to ensure its performance. A complete shielding system requires shielding everywhere. Once any point of shielding can not meet the requirements, it will inevitably affect the overall transmission performance of the system.