The difference between shielded twisted pair and unshielded twisted pair

Twisted pair wires can be divided into shielded and unshielded. The following content will be described in detail.

Unshielded Twisted Pair UTP

Unshielded twisted pair has no metal shielding material, only one layer of insulation wrapping, light weight, more convenient in the environment that requires corner installation, strong flexibility and independence, and is also suitable for structured wiring.

Shielded twisted pair STP

Shielded twisted pair has an extra layer of shielding than unshielded twisted pair, which can provide a clearer electrical signal, and its outer layer is wrapped with aluminum foil to reduce radiation.

In 10G copper cabling, there are the following twisted pairs:

Whether it is cat6, cat6a or cat7, there are shielded and non-shielded types to choose from. In the above description, we know the advantages of shielded and unshielded twisted pair cables. In fact, they also have their own advantages and disadvantages, so which one would you choose? Best performance for 10G 10G copper network?

1. Signal interference

In practical applications, part of the energy of a pair of cores in the same cable will leak into other cores due to electromagnetic coupling. This effect is called "crosstalk" and it not only interferes with the signal transmission of adjacent cores, but also with the signal transmission of other cables. Usually, near-end alien crosstalk and far-end alien crosstalk are used to detect the degree of interference.

Since the unshielded twisted pair has no shielding layer, in order to reduce the external crosstalk, the manufacturer generally increases the distance between the wire cores, and strictly suppresses the crosstalk on the internal connector to achieve a transmission distance of 100 meters. If not. Unshielded twisted pair often cannot meet the alien crosstalk limit required for transmission of 100 meters; while the structure of shielded twisted pair itself can effectively prevent signal crosstalk.

2. use

In wiring construction, the twisted pair must match the connector to connect to the device. Generally use RJ45 crystal head. For the convenience of operation, some manufacturers make finished products according to different meters when producing twisted pairs. Network cable (no need to make a crystal head), fixed meter application has certain limitations, so most people would rather buy bulk twisted pair cables and terminate them by themselves during construction.

Due to the characteristics of the shielded twisted pair structure, it has more full shielding layers than the unshielded twisted pair, and has wires and metal foils to eliminate interference.

3. Grounding

One of the shielded twisted pairs is the ground wire, which is used to lead the current to the ground wire. When electrical equipment leaks electricity or the voltage is too high, the current enters the earth through the ground wire. The shielding layer will generate a certain amount of charge due to external electromagnetic interference. In order to play a shielding role, it needs to be grounded to discharge the charge. 10G 10 Gigabit copper systems are very sensitive to noise. If the grounding is not good, the shielding effect will not be achieved, and the attenuation will increase during signal transmission, which will affect the speed. stranded.

4. Cost

The cost of wiring with a shielded twisted pair system is higher than that of an unshielded twisted pair system. First of all, the shielded twisted pair has more shielding layers and the materials are more expensive.