What can disturb the CAT 5 cable

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Twisted pair cable

A twisted pair consists of two copper wires, each with individual plastic insulation, both of which are wired in isolation and twisted together. To complete the circuit, one of the wires is used to carry the signal to the receiver and the other wire is only used as a ground reference to calculate the difference between the two. Together with the signal that the transmitter sends on one of the lines, interference and crosstalk can disturb the lines and generate unwanted signals.
If both wires run in parallel along the transmission path, the effect of these unwanted signals is not the same in both wires, since they are in different places compared to the sources of noise or crosstalk. When one wire of the pair is closer and the other is farther from sources of crosstalk. The influence of interference on a single line leads to a difference on the receiving end. The twists introduced in the wires are used to even out the impact on both wires, rather than hitting one wire, both wires are equally affected by the source of interference or crosstalk. The receiver is not receiving any unwanted signals at the time of calculating the difference between two wires. The unwanted signals are usually canceled by twisting wires. It should be noted that twisting, usually per inch of length, has some influence on the quality of the cable.

Shielded vs. unshielded

Unshielded twisted pair, commonly known as UTP, is the most common type of twisted pair cable used in communications. However, the shielded twisted pair cable (STP) was introduced by IBM in 1985. Even though STP was introduced by IBM in which each cable pair was shielded with aluminum foil, along with an overall shield for the already shielded pairs. The shielding leads to protection against external influences. However, despite the fact that the metal housing increases the quality of the cable by preventing interference or crosstalk from entering, it is larger and more expensive.
In addition to the IBM standard shielded twisted pair cable, there are also other shielding standards. Some produce cables by shielding only the single pair, others produce cables that are shielded as a whole, while others produce overall shielding and individual pairs as well.

Categories of ETVs

The international standard ISO / IEC 11801 defines several categories of twisted copper cables, each of which differs in terms of maximum bandwidth, distance and data rate. You will find the categories of standards below:

Cat 1 cable:

Cat. 1, Category 1, also known as Level 1, is a type of unshielded twisted pair cable that is used for telephone communications. The maximum bandwidth supported by this cable is 1 MHz. However, Cat 1 is not an authorized category standard developed by TIA / EIA; Category 1 has basically become the name for Level 1 cables. These cables are typically used on networks that only carry voice traffic, such as telephones.

Cat 2 cable:

The Category 2 or Category 2 cable is an unshielded twisted pair. This cable is intended for telephone and data communication. The maximum bandwidth supported by the cable is 4 MHz, and the maximum data rate of 4 Mbit / s can be achieved.

The TIA / EIA-568 standards were officially set for Category 3 or higher cables.

Cat 3 cable:

Cat 2 or Category 3 cable, sometimes known as Voice-Grade (VG), is an unshielded twisted pair (UTP) cable used in telephone wiring. The maximum bandwidth supported by the cable is 16 MHz, and the maximum data rate of 10 Mbit / s can be achieved with these cables.

Cat 4 cable:

The Category 4 or Category 4 cable consists of four unshielded twisted pairs (UTP) made of copper. Cat4 is used in telephone networks that can transmit voice and data. The maximum bandwidth supported by the cable is 20 MHz, and the maximum data rate of 16 Mbit / s can be achieved with these cables.

Cat 5 cable:

Cat 5 or Category 5 is an unshielded, twisted pair cable. This type of cable has been widely used on computer networks. The maximum bandwidth supported by the cable is 100 MHz and the maximum data rate 100 Mbit / s. The Cat 5 cable is suitable for the standards 10BASE-T, 100BASE-TX (Fast Ethernet).
Category 5 was replaced by the extended specification of Category 5e and later by Category 6 cables.

Cat5e cable:

Cat5e, also known as Category 5 enhanced, is an advanced Cat-5 cable that supports 1000BASE-T (Gigabit Ethernet). The differences between Category 5 and Category 5e lie in the transmission capacity. The maximum bandwidth supported by the cable is the same as that of Cat 5, which is 100 MHz, but the data rate of 1000 Mbit / s can be achieved.

Cat 6 cable:

Cat6 cable, usually referred to as Category 6, is a standardized twisted pair cable. The Cat 6 cable is compatible with the previous standard cables of Category 5 / 5e. Related to Cat 5 and Cat 5e, Cat 6 maximum bandwidth supported by cable 250 MHz, it is capable of 10GBASE-T (Giga Ehternet).

Cat6a cable:

The Cat6a cable is an evolution of Cat6 that offers improved performance. Cat6a can support double the bandwidth of Cat6, i.e. 500 MHz, which is supported by Cat6a. In addition to the bandwidth, Cat6a can also support a data rate of 1000Mbps for longer distances compared to Cat6. Cat6a is also shielded, unlike Cat6 and earlier standards which were unshielded. Either individual twisted wire pairs are shielded or overall shielding is provided for Cat6a in order to reduce interference from external sources.

Cat 7 cable:

Cat 7 or Category 7 is a fully shielded twisted pair cable, both copper pairs are shielded and provided with an over-shielding. The maximum bandwidth supported by the cable is 600 MHz. The Cat 7 cable is suitable for either 10GBASE-T (Giga Ethernet) or 100BASE-TX, POTS and CATV standards on a single Cat 7 cable.

Cat 7 A cable:

Cat 7 A cable is a fully shielded, twisted pair cable. The maximum bandwidth supported by the Cat 7 A cable is 1000 MHz. A summary of the above cable standards can be given in the following table.

Cable standard




Category 1

1 MHz

Telephone traffic

Category 2

4 MHz

Telephone traffic

Category 3


16 MHz

Telephone and Modem

Category 4


20 MHz

Category 5


100 MHz


Category 5e


100 MHz


Category 6


250 MHz


Category 6A

U / FTP, F / UTP

500 MHz


Category 7


600 MHz

100GBASE-T or POTS / CATV / 1000BASE-T

Category 7A


1000 MHz

100GBASE-T or POTS / CATV / 1000BASE-T

U / FTP = individual twisted wire pairs are shielded.
F / UTP = overall shielding
F / FTP = single pairs and overall shielding


Even if unshielded twisted pair (UTP) and shielded twisted pair (STP) cables have their own advantages and disadvantages and are best used depending on the requirements.

However, both STP and UTP are capable of suppressing interference, but both are designed to suppress interference in different ways. Power lines and high-performance electromagnetic signals can cause interference. STP cables have a metallic, foil-conductive shield for coating the twisted pairs, which excludes interference and enables data to be transmitted more quickly. STP cables have several disadvantages. STP cables are larger than UTP cables. STP cables are also more expensive. STP cables are best for use in an industrial environment with high levels of electromagnetic interference, such as a factory.

UTP cables are commonly used cables for Ethernet connections and have several advantages. They depend on the cancellation effect created by the twisting of the wire pairs, which must be suitable for most normal applications. UTP are also smaller than STP cables, smaller dimensions make installation easier. UTP cables are also cheaper than STP cables and require little maintenance. They are best suited for use in home and office connections and anywhere where there is not much electromagnetic interference.