Which RJ45 Twisted Pair Patch Cord is Right Choice for my Network

Twisted pair cable

A twisted pair comprises of two copper wires, each having its individual plastic insulation, both insulated wired are twisted together. For completing the circuit, one of the wire is used to transmit the signal to the receiver, and the other wire is used only as ground reference to calculate the difference between two. Along with the signal sent by the sender on one of the wires, the interference and crosstalk may disturb wires and generate undesirable signals.

If both wires are parallel along the transmission path, the effect of these undesirable signals is not same in both of the wires, since they are at different locations comparative to the noise or crosstalk sources. If one wire from the pair is nearer and the other is farther from the crosstalk sources. The impact of interference on a single wire will result in a difference at the receiver end. The twists introduced into the wires are used to balance the impact on both wires, rather impacting one wire, both wires are equally impacted by the interference or crosstalk source. The receiver receives no undesirable signals at the time of calculating difference between two wires. The undesirable signals are mostly canceled out by twisting wires. It must be noted that twists, usually per inch of length, ensures some effect on the quality of the cable.

Shielded vs unshielded

Unshielded twisted-pair, commonly referred as UTP, is the most common type of twisted pair cable used in communication. However shielded twisted pair cable (STP) was introduced by IBM in 1985. Even if STP was introduced by IBM, in which each pair of cable was shielded with aluminum foil along with an overall shielding for the already shielded pairs. The shielding results in protection from external interference. Despite the fact the metal casing increases the quality of cable by blocking the penetration of interference or crosstalk, but it is bulkier and more expensive.

Apart from the IBM standard shielded twisted pair cable, there are also other shielding standards. Some manufacture cable by shielding the individuals pair only, some produce cable which are overall shielded, where as some shield overall as well as individual pairs also.

Categories of UTP

International standard ISO/IEC 11801 standard defines several categories of twisted-pair copper cable, each differ in the maximum bandwidth, distance and data rate achieved. Below are the categories standards:

Cat 1 cable:

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

Cat 2 Cable:

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

TIA/EIA-568 standards have been officially established for cables of Category 3 ratings or above.

Cat 3 Cable:

Cat 2, or Category 3 cable and sometimes known as voice-grade (VG) is an unshielded twisted pair (UTP) cable used in telephone wiring. The maximum bandwidth supported by cable is 16 MHz, and the maximum data rate of 10 Mbps can be accomplished using these cables.

Cat 4 Cable:

Cat 4 or Category 4 cable comprises of four unshielded twisted-pair (UTP) of copper. Cat4 is used in telephone networks that can transmit voice and data. The maximum bandwidth supported by cable is 20 MHz, and the maximum data rate of 16 Mbps can be accomplished using these cables.

Cat 5 Cable:

Cat 5 or Category 5 is an unshielded twisted pair cable. This type of cable was widely used in computer networks. The maximum bandwidth supported by cable is 100 MHz, and the maximum data rate of 100 Mbps. The Cat 5 cable is appropriate for 10BASE-T, 100BASE-TX (Fast Ethernet) standards.

Category 5 was succeeded by the Category 5e enhanced specification, and later category 6 cable.

Cat5e Cable:

Cat5e also known as Category 5 enhanced, is an advanced cat 5 cable capable of supporting 1000BASE-T (Gigabit Ethernet). The differences between Category 5 and Category 5e are in their transmission performance. The maximum bandwidth supported by cable is same as Cat 5, which is 100 MHz, but the data rate of 1000 Mbps can be achieved.

Cat 6 Cable:

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

Cat6a cable:

Cat6a cable is advancement to Cat6 which delivers enhanced performance. Cat6a can support bandwidth twice that of Cat6 that is 500 MHz is supported by Cat6a. Beside bandwidth, Cat6a can support 1000Mbps data rate for longer distances as compare to Cat6. Also Cat6a is shielded, unlike Cat6 and previous standards which were unshielded. Either individual pairs of twisted wires are shielded or an overall shielding is provided to Cat6a to reduce interference from external sources.

Cat 7 Cable:

Cat 7 or Category 7 is a fully shielded twisted pair cable, both the copper pairs are shielded along with an over shield. The maximum bandwidth supported by cable is 600 MHz. The Cat 7 cable is suitable, either for 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 Cat 7 A cable is 1000 Mhz.

Summary of above cable standards can be given in below table.

U/FTP = individual pairs of twisted wires are shielded
F/UTP = overall shielding
F/FTP = individual pairs as well as overall shielding

Applications

Even if unshielded twisted pair (UTP) and shielded twisted pair (STP) cables have their own pros and cons and best application depending upon the requirement.

However both STP and UTP have capability to cancel out interference, but both are designed to cancel interference in different ways. Power lines and high power electromagnetic signals can cause interference. STP cables have a metallic foil conducting shield for coating the twisted pairs, which blocks out interference, letting it to transmit data at a faster rate. STP cables have some disadvantages. STP cables are bigger than UTP cables. Also STP cables are more expensive. STP cables are best if used in industrial environment, where high amount of electromagnetic interference, like a factory.

UTP cables are normally used cables for ethernet connections, and have a few advantages. They depend on the cancellation affect produced by the twisting of the wire pairs, which is must suitable for most normal uses. UTP are also smaller in size than STP cables, smaller size makes them easier to install. UTP cables are also inexpensive than STP cables, and do not need much maintenance. They are best to be used in home and office connections, and in any area where there is not a much of electromagnetic interference.