Discuss noise effect on twisted pair. State the reasons why fiber optic cables provide
better performance than twisted pair and coaxial cables. What is the purpose of
cladding in a fiber optic?
Answers
Answer:
Fiber optic cable, twisted pair cable and coaxial cable are three major types of network cables used in communication systems. Each of them is different and suitable for different applications. Since each of them can be equally applied into network communication, how they distinct from each other in terms of features and specifications? What’s the differences between performance and capacity when it comes to fiber optic cable vs twisted pair cable vs coaxial cable?
Fiber Optic Cable
Fiber optic cable, also called as optical fiber cable, is a type of Ethernet cable which consists of one or more optic fibers that are used to transmit data. Fiber optic cable transmits data as pulses of light go through tiny tubes of glass. The transmission capacity of optical fiber cable is 26,000 times higher than that of twisted pair cable.
Fiber optic cable
Figure 1: Fiber optic cable
Fiber optic cable can be divided into single mode fiber (SMF) and multimode fiber (MMF). Single mode optical fiber has a small core, and only allows one mode of light to propagate at a time. While multimode fiber cable comes with a larger core and is designed to carry multiple light rays or modes at the same time. The common single mode fiber cable is OS2 cable, and multimode fiber cable is OM1, OM2, OM3, OM4, and OM5. And the transmission distance of single mode fiber cable is up to several kilometers, while the multimode fiber is up to 550 meters over 10G network. To know more details about fiber optic cable types, working principle and installation tips, please read: Fiber Optic Cable Guide: Fiber Optic Cable Types and Installation
Twisted Pair Cable
Twisted pair cable is often used for telephone communications and most modern Ethernet networks. It is a kind of wiring in which two conductors of a single circuit are twisted together. A pair of wires forms a circuit that can transmit data. And the pairs are twisted together to provide protection against crosstalk, the noise generated by adjacent pairs.
Shielded twisted pair
Figure 2: Shielded twisted pair
There are two types of twisted pair Ethernet cable: unshielded twisted pair (UTP) and shielded twisted pair (STP). The commonly used UTP copper cable is Cat5, Cat5e, Cat6, Cat6a and Cat7. The STP copper cable has a foil-wrapped outside on each pair of wires. The four pairs of wires then are wrapped in an overall metallic braid or foil, usually 150-ohm cable. STP cable has a better capacity of resisting noise than UTP cable, even if both of them can be used in 10GBASE-T. Know the difference between UTP and STP cable in 10GBASE-T network: UTP or STP Cables for 10GBASE-T Network?
Coaxial Cable
Coaxial cable, or coax cable, is designed to transmit high-frequency signals. It’s comprised of a round copper conductor and three layers of insulation and shielding which prevents crosstalk from motors, lighting and other sources of EMI. With the shield construction, the coaxial cable can support longer cable lengths between two devices.
Coaxial cable
Figure 3: Coaxial cable
There are a number of different types of coax, but only two—RG59 and RG6—get the most use in residential applications. The name “RG” dates back to World War II and means “radio guide” which doesn’t have really signify anything today.
Coaxial Cable Types