Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. Twisted pair comes with each pair uniquely color coded when it is packaged in multiple pairs. The wire you buy at a local hardware store for extensions from your phone or computer modem to a wall jack is not twisted pair. It is a side-by-side wire known as silver satin. Two different types of twisted pair cable, unshielded twisted pair (UTP) and shielded twisted pair (STP) are used in different kinds of installations.
source: https://www.techopedia.com/definition/13433/twisted-pair-cable
a. Shielded Twisted Pair
Shielded twisted pair is a special kind of copper telephone wiring used in some business installations. An outer covering or shield is added to the ordinary twisted pair telephone wires; the shield functions as a ground. STP is similar to unshielded twisted pair (UTP); however, it contains an extra foil wrapping or copper braid jacket to help shield the cable signals from interference. STP cables are costlier when compared to UTP, but has the advantage of being capable of supporting higher transmission rates across longer distances.
b. Unshielded Twisted Pair
Unshielded twisted pair (UTP) cables are widely used in the computer and telecommunications industry as Ethernet cables and telephone wires.
In an UTP cable, conductors which form a single circuit are twisted around each other in order to cancel out electromagnetic interference (EMI) from external sources. Unshielded means no additional shielding like meshes or aluminum foil, which add bulk, are used.
UTP cables are often groups of twisted pairs grouped together with color coded insulators, the number of which depends on the purpose.
B. Coaxial
Coaxial cable is a type of copper cable specially built with a metal shield and other components engineered to block signal interference. It is primarily used by cable TV companies to connect their satellite antenna facilities to customer homes and businesses. It is also sometimes used by telephone companies to connect central offices to telephone poles near customers. Coaxial cable received its name because it includes one physical channel that carries the signal surrounded.
source: https://www.techopedia.com/definition/coaxial
source: https://www.techopedia.com/definition/coaxial
C. Fiber Optic
Fiber optics, or optical fiber, refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic strand or fiber. A fiber optic cable can contain a varying number of these glass fibers -- from a few up to a couple hundred. Surrounding the glass fiber core is another glass layer called cladding. A layer known as a buffer tube protects the cladding, and a jacket layer acts as the final protective layer for the individual strand.
Straight-through cable is a type of twisted pair copper wire cable for local area network (LAN) use for which the RJ-45 connectors at each end have the same pinout (i.e., arrangement of conductors).
It is identical to crossover cable, except that in the latter the wires on the cable are crossed over so that the receive signal pins on the connector on one end are connected to the transmit signal pins on the connector on the other end.
Straight-through cable is also commonly referred to as patch cable. However, this might be confusing in some situations because patch cable also has a broader definition that emphasizes the fact that there is a connector on each end rather than the equality (or lack thereof) of the pinouts.
Straight-through cable is used to connect computers and other end-user devices (e.g., printers) to networking devices such as hubs and switches. It can also be used to directly connect like devices (e.g., two hubs or two switches) if the cable is plugged into an uplink port on one (but not both) of the devices. Crossover cable is used to connect two like devices without the use of an uplink port.
No comments:
Post a Comment