Twisted Pair
It is the most common type of cable and originated as a solution to connect telephones, terminals and computers on the same wiring. Previously, in Europe, telephone systems used untwisted pair cables.
Each cable of this type is made up of a series of pairs of twisted cables. The pairs are twisted to reduce interference between adjacent pairs. Typically a number of pairs are bundled into a single color coded jacket to reduce the number of physical cables running in a conduit.
The number of pairs per cable are 4, 25, 50, 100, 200 and 300. When the number of pairs is greater than 4, we speak of multipair cables.
TYPES OF BRAIDED CABLE
UNSHIELDED (UTP): It is the normal twisted pair cable and is referred to by its acronym in English UTP (Unshielded Twisted Pair). The biggest advantages of this type of cable are its low cost and ease of handling. Its biggest disadvantages are its higher error rate compared to other types of cable, as well as its limitations to work at long distances without regeneration.
For the various local area network technologies, unshielded copper pair cable has become the most widely used cabling system.
The EIA-568 standard in the TSB-36 addendum differentiates three different categories for this type of cable:
- Category 3: They support frequencies up to 16 Mhz and are often used in IEEE 802.3 10BASE-T and 802.5 4 Mbps networks.
- Category 4: They support frequencies up to 20 Mhz and are used in IEEE 802.5 Token Ring and Ethernet 10BASE-T networks for long distances.
- Category 5: They support frequencies of up to 100 Mhz and are used for applications such as TPDDI and FDDI among others.
the wires of category 1 and 2 they are used for voice and low-capacity data transmission (up to 4Mbps). This type of cable is ideal for telephone communications, but the speeds required by networks today require better quality.
The general characteristics of the UTP cable are:
Size: The smaller diameter of unshielded twisted pair cables allows for more efficient use of ducts and distribution cabinets. The typical diameter of these cables is 0 mm.
Weight: The low weight of this type of cable compared to other types of cable facilitates laying.
Flexibility: The ease of bending and bending this type of cable allows faster laying as well as the connection of outlets and strips.
Installation: Due to the widespread use of this type of cable, there is a wide variety of suppliers, installers and tools that make installation and commissioning cheaper.
Integration: The services supported by this type of cable include:
- Local Area Network ISO 8802.3 (Ethernet) and ISO 8802.5 (Token Ring)
- analog telephony
- digital telephony
- Synchronous terminals
- asynchronous terminals
- Control lines and alarms
SHIELDED (STP): Each pair is covered with a metal mesh, in the same way as coaxial cables, and the set of pairs is covered with a shielding foil. It is frequently referred to by its acronym in English STP (Shield Twisted Pair / Shielded Twisted Pair).
The use of a shielding mesh reduces the error rate, but increases the cost by requiring a more expensive manufacturing process.
UNIFORM (FTP):Each of the pairs is uniformly twisted during its creation. This eliminates most cable-to-cable interference and also protects the cable assembly from outside interference. A global shielding of all the pairs is carried out by means of an external shielding sheet. This technique allows for similar characteristics to shielded cable with slightly lower costs per meter. This is used within category 5 and 5e (up to 100 Mhz).