media structure and configuration of treasuries.
The main purpose of the physical structure of the network is to transport, as a stream of bits, information from one machine to another.
The main hardware transmission for LANs are
* shielded twisted pair cable (shielded) or unscreened (unshielded)
* Coaxial Fiber Optic
*
There are two types for data transmission: 1 .- Middle
guided .- Includes metal wire (copper, aluminum, etc.) and fiber optic cable. The cable is typically installed on buildings or through hidden. Include metal wires twisted pair cable and coaxial cable, where copper is the material of choice for building transmission networks. The optical fiber is available in single or multiple strands of fiberglass or plastic. Second
2 .- Middle unguided .- This refers to techniques for signal transmission in the air or space from transmitter to receiver. In this category is the infrared and microwave.
Structure and twisted pair cable configurations
* In general, the structure of all twisted pair cables differ significantly. The cable is composed of an inner conductor which is electrolytic annealed wire, circular type, insulated by a layer of colored polyethylene.
* Below the colored insulation there is also another layer of polyethylene insulation, which contains in its composition an antioxidant substance to prevent corrosion cable. The conduit has a diameter of only about half a millimeter, and more insulation can exceed the diameter of a millimeter.
insulation colors are standardized to manipulation by large amounts. LAN standard colors are:
* Orange / White - Orange
* Green / White - Green.
* White / Blue - Blue
* White / Brown - Brown
TWISTED PAIR INSTALLATION:
* Sometimes there may be doubts how to correctly perform the ferrule connector twisted-pair (TP), how installing a rosette or grimpaje panel. So we've included a chart where you can see what is the right approach.
straight cable (pin to pin)
are the cables that connect a hub to a network node (Hub, Node) are Crimped wires to RJ-45 connectors each on both ends. All pairs of colors (white / blue) are connected in the same positions on both ends. The reason is that the hub internally performs the necessary signal crossing.
The rule 568B and the order of colors of the pair of cables. In crossover cable to use another computer known as the 568A standard. One of the rules will be applied in one end of the cable and the other in the other end, no matter which standard on every computer you connect two computers only.
crossover cable (crossover)
* These cables that connect two hubs or two transceivers each other, or even two cards (Node-Node), a distance not exceeding 10 m. The pair 2 (pins 1 and 2) and the pair 3 (pins 3 and 6) are crossed
* The crossover cable (crossover) may only be used when a PC is connected directly to another PC, without there being any additional element (hubs, routers, etc.).. Structure
coaxial cable * Coaxial cable consists of a solid copper core surrounded by an insulator, a combination of shielding and ground wire and some other protective cover.
There are essentially two types of coaxial cables:
* For transmission over broadband.
* With a characteristic impedance of 75 ohmios.Utilizado in signal transmission cable TV (CATV, "Cable Television").
* For base-band transmission.
* With a characteristic impedance of 50 ohms. Used in LAN's. Within this category, we use two types of cables: coaxial coarse ("thick") and thin coax ("thin"). Coaxial
thickness ("thick"):
* is the largest cable used in LAN's at the beginning and even today is still used in certain circumstances (high degree of interference, distances, etc..).
* The diameters of the soul / mesh are 2.6 / 9.5 mm. And the cable's total of 0.4 inches (about 1 cm.). Connector is used as a transceiver (transceiver) relatively complex, since its entry into the cable involves drilling to the core (coaxial cable drop by an element type "vampire" or "tap")
thin coaxial cable ( thin)
* emerged as an alternative to the cable above, to be cheaper, flexible and easy to install.
* Diameters of his soul / mesh are 1.2 / 4.4 mm, and the cable only 0.25 inches (just over 0.5 cm.). However, its transmission properties are significantly worse than the thick coaxial.
* This used thin coaxial BNC (British National Connector ") simple and high quality offer more security than those of a" tap ", but require prior knowledge of the connection points.
* Until recently, it was the most common means of transmission in local networks.
coaxial cable configurations
* Factors to consider when choosing a coaxial cable is its bandwidth, its resistance or characteristic impedance, capacity and speed of propagation.
* The bandwidth of coaxial cable is between 500Mhz, this makes the ideal coaxial cable for cable television transmission of multiple channels.
* The resistance or characteristic impedance depends on the thickness of the central conductor or screen, if it varies, so does the characteristic impedance.
fiber structure
adjusted * Structure: consists of a plastic tube or sheath inside which is housed in a stable manner, the optical fiber. They can be both single-fiber cables, as multifiber. Its most common applications are: short distances, campus facilities, indoor facilities, installations in conduit, direct connector assembly and installation of hoses.
* loose structure: instead of a single conductor are introduced from two to twelve optical fibers on a deck somewhat larger than the sheath of the previous case, this way fiber drivers are not adjusted to the sheath. You can usually cover the whole with a gel that does not penetrate the water in case of cable breakage. Mainly multi-fiber cables are divided into armed (moisture and antirroedores with steel) and dielectric multifiber cables (All Dielectric cable).
* The two types of fiber are:
* single mode (single mode)
* Multimode (multimode)
* The single-mode optical fiber is used for trunk connections are basically installed by the providers of public services because it allows the use of amplifiers at a distance between them of 40 km or more, while copper transmission lines takes three amplifiers every 10 km
* Instead multimode fiber is installed in buildings commercial offices, banks and offices where cabling distance between centers is less than 2 km
* Each of these types of FOR, having a core of different diameters, and single-mode fiber has a core of 9 microns, and the multi-enters the market with two measures: the fiber with 62.5 micron core and the new version in 50 microns.
* For reference indicated that the diameter of human hair is 70 microns.
* The optical fiber allows different nominal wavelengths, ranging between 850nm and 1550nm under the following headings:
* FOR 1000 Base SX (is within the window of 850nm - "short")
* FO 1000 Base LX (is within the 1300nm window - "long")
The fiber optic connectors are most commonly used commercially:
* ST, metal, with ceramic ferrule, securing a bayonet used in multimode, with polished convex PC. I screwed up and connected by mechanical welding, epoxy material.
* SC, plastic, ceramic ferrule, securing push-pull, single or duplex, used in both multimode and singlemode, with PC and APC polishing convex in three different colors: blue for single mode, beige for multimode and green for long distance.
* FC, similar to ST but threaded.
* FDDI * D4 * Biconic
* * ESCON SMA
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