What are the TYPES OF CABLES?
- Despite advances in wireless technologies, many computer networks in the
21st century still rely on cables as a physical medium for devices to
transfer data. Several standard types of network cables exist, each designed for specific purposes.
TYPES OF CABLES
1. TWISTED-PAIR CABLES
→ A type of cable that consists of two independently insulated wires
twisted around one another. The use of two wires twisted together helps
to reduce crosstalk and electromagnetic induction. While twisted-pair cable is used by older telephone networks and is the least expensive type of local-area network (LAN)
cable, most networks contain some twisted-pair cabling at some point
along the network. Other types of cables used for LANs include coaxial cables and fiber optic cables.
→ Two primary types of twisted pair cable industry standards have been defined: Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP).
a. SHIELDED TWISTED PAIR (STP)
→ Often abbreviated STP, a type of copper telephone wiring in
which each of the two copper wires that are twisted together are coated
with an insulating coating that functions as a ground for the wires. The
extra covering in shielded twisted pair wiring protects the
transmission line from electromagnetic interference leaking into or out of the cable. STP cabling often is used in Ethernet networks, especially fast data rate Ethernets.
b. UNSHIELDED TWISTED PAIR (UTP)
→ UTP stands for Unshielded Twisted Pair cable. UTP cable is a 100 ohm
copper cable that consists of 2 to 1800 unshielded twisted pairs
surrounded by an outer jacket. They have no metallic shield. This makes
the cable small in diameter but unprotected against electrical
interference. The twist helps to improve its immunity to electrical
noise and EMI.
2. COAXIAL CABLE
→ Invented in the 1880s, "coax" was best known as the kind of cable that
connected television sets to home antennas. Coaxial cable is also a
standard for 10 Mbps Ethernet cables.
When 10 Mbps Ethernet was most popular, during the 1980s and early
1990s, networks typically utilized one of two kinds of coax cable - thinnet (10BASE2 standard) or thicknet
(10BASE5). These cables consist of an inner copper wire of varying
thickness surrounded by insulation and another shielding. Their
stiffness caused network administrators difficulty in installing and
maintaining thinnet and thicknet.
3. FIBER-OPTIC CABLE
→ An optical fiber cable, also known as a fiber optic cable, is an assembly similar to an electrical cable, but containing one or more optical fibers
that are used to carry light. The optical fiber elements are typically
individually coated with plastic layers and contained in a protective
tube suitable for the environment where the cable will be deployed.
Different types of cable are used for different applications, for example long distance telecommunication, or providing a high-speed data connection between different parts of a building.
Difference between Straight-through cable and Cross-over cable
- Ethernet cables can be wired as straight through or crossover. The
straight through is the most common type and is used to connect
computers to hubs or switches. They are most likely what you will find
when you go to your local computer store and buy a patch cable.
Crossover cable is more commonly used to connect a computer to a
computer and may be a little harder to find since they aren’t used
nearly as much as straight through cable. Then, what’s the difference
between them? Difference between straight through and crossover cables
will be introduced in this blog.
Straight Through Cable
→ A straight through cable is a type of twisted pair cable that is used in
local area networks to connect a computer to a network hub such as a
router. This type of cable is also sometimes called a patch cable and is
an alternative to wireless connections where one or more computers
access a router through a wireless signal. On a straight through cable,
the wired pins match. Straight through cable use one wiring standard:
both ends use T568A wiring standard or both ends use T568B wiring
standard. The following figure shows a straight through cable of which
both ends are wired as the T568B standard.
Cross-over Cable
→ An Ethernet crossover cable is a type of Ethernet cable used to connect
computing devices together directly. Unlike straight through cable,
crossover cables use two different wiring standards: one end uses the
T568A wiring standard, and the other end uses the T568B wiring standard.
The internal wiring of Ethernet crossover cables reverses the transmit
and receive signals. It is most often used to connect two devices of the
same type: e.g. two computers (via network interface controller) or two
switches to each other.
- Usually, straight through cables are primarily used for connecting
unlike devices. And crossover cables are use for connecting unlike
devices alike devices.
Conclusion:
⇒ Straight through and crossover cables are wired differently from each
other. One easy way to tell what you have is to look at the order of the
colored wires inside the RJ45 connector. If the order of the wires is
the same on both ends, then you have a straight through cable. If not,
then it’s most likely a crossover cable or was wired wrong. At present,
the straight through cable is much more popular than crossover cable and
is widely used by people.
Sources:
https://www.lifewire.com/introduction-to-network-cables-817868
https://www.webopedia.com/TERM/T/twisted_pair_cable.html
https://www.webopedia.com/TERM/S/shielded_twisted_pair.html
https://www.fiberoptics4sale.com/blogs/archive-posts/95046918-what-is-unshielded-twisted-pair-utp-cable
https://en.wikipedia.org/wiki/Optical_fiber_cable
http://www.cables-solutions.com/difference-between-straight-through-and-crossover-cable.html