needed a transmission medium to transmit information from the source to the destination. The information is usually a sign that you have to travel a long distance. To do so, the transmission medium can be wired or wireless. Wired transmission signal passes the cable from one device to another. But the wireless transmission are transmitted without a physical conductor of electromagnetic waves. Three types of cables, for example.
twisted-pair cable 1-
2 coaxial cable
3 fiber optic cable
The two twisted-pair cable copper conductors, each with its own plastic insulation and twisted together. A wireless signal and the other is used to ground reference. The advantage of twisting is that both wires also touched against external influences. So the unwanted signals are canceled out as the receiver calculates the difference between the two signal wires.
This two types of cables, for example.
1- UTP (unshielded twisted pair)
2- STP (shielded twisted pair)
STP cable plus a metal shield, which is insulated twisted pairs. But it lacks UTP cable. The most common UTP RJ45 connector.
The unshielded twisted pair cable is classified into seven categories based on quality. Category 1 cables used in telephone lines, the data transfer rate of about 0.1 Mbps. As used in Category 5 LAN with a 100 Mbps data transfer rate.
Performance of twisted-pair cable is measured by comparing attenuation is a function of frequency. Damping increases frequencies above 100 kHz.
These cables are used for phone lines to voice and data channels. DSL lines and Local Area Networks twisted pair cables.
coaxial cable (coax) carries high frequency signals than twisted-pair cables. Coax central core conductor solid wire enclosed insulation which an outer conductor of aluminum foil. This outer conductor completes the circuit. External driver closed an insulator, and the whole cable is protected by a plastic cover.
These cables are categorized based RG (radio government). RG-59 used for Cable TV, RG-58 Ethernet thin and thick RG-11 Ethernet. The connector used in these cables is called BNC connector; It is used to connect the end of the cable to a device.
Although the coaxial cable greater bandwidth, but the attenuation is much higher compared to twisted-pair cables. It is widely used in digital telephone networks where a single cable can carry data at speeds up to 600 Mbps. Cable TV networks use RG-59 coaxial cable. Traditional Ethernet LANs also use this cable.
The fiber optic cable transmits signals in the form of light. Using optical fibers to guide the reflection of light over a single channel. It consists of two main parts: core and cladding. Core is denser compare and cover made of plastic or glass. Housing Works guard core. The difference between the density of the core and cladding so that a light beam passing through the core is reflected from the casing, rather than being broken into.
There are two possible modes of propagation of light optical fiber, such as: multi and single mode. Multimode fiber allows multiple beams from a light source to move through the core. Multimode step-index fibers, the core density remains constant from the center to the edge. But in multimode graded-index fiber core density gradually decreases from the center, the core, to the edge. Graded index fiber creates less distortion in the signal compare the step-index.
Two types of connectors for fiber optic cables. The SC connectors used for cable TV, and ST connector used for connecting cable to networking devices. Attenuation of fiber optic cable is very low compare to other two. It provides high bandwidth and immunity to electromagnetic interference. Light weight and greater immunity to tapping makes it advantageous cable.
fiber optic backbone networks are often used for high-bandwidth and cost efficiency. Local networks such as 100Base-FX network and 100Base-X use this cable. It is also used in cable television companies.