With advances in technology twisted pair cable and connections that allow rates of 10 gigabit ethernet networks transfers in kind, because using fiber networks where you can use the pair cable 100m twisted?
The answer to that perhaps lies in the fact that the connections where you can use UTC or STC cable still use it. There are rare occasions where a connection by optical fiber is used without the impossibility of using the twisted pair, such as large parts of the link (above twisted pair cable 100m) or links that pass through areas of high electromagnetic interference (plants electrical, substations).
But if the fiber is used in over 100m connections, why not use connections with shorter distances? The answer to that question is simple: price. Fiber optic equipment such as terminal or repeaters are very expensive, which prevents their use in small networks. Because of this there is a range of equipment, not only for the use of the network, but their interconnection with the local network, where the predominant twisted pair.
As the optical fiber networks are used in long-distance networks and local networks use wired networks, the first device that is found in fiber optic networks are the equipment that perform this interconnection. These are the terminal equipment.
Terminal equipment are usually multiplexers receiving multiple connections twisted pair cable networks and transmitted over an optical fiber network. Its function is to simply get the information that travels in the optical network and translate into electrical pulses for transmission by cables.
It is worth noting however that with the advancement of wired networks and the demands of some companies (or people with excellent financial conditions) for ever faster internet connections, already on the market fiber optic converters equipment for twisted pair cable with only a connection.
Even if the fiber has a low signal attenuation, there is the need to regenerate that signal while the distances are becoming larger. Remove this signal, process and send this signal by the network again can not be a good idea, as well raise the cost and add a delay in the network (the optical signal conversion time for electrical signal and the electrical signal to optical signal again) .Therefore there is a need for a device that regenerates this signal without the need for conversion of these signals. This is the line amplifier.
These devices regenerate the optical signal with all wavelengths (there may be several wavelengths, each carrying different information on the same cable). However, they also amplify the noise (signals that do not make sense on the network). So when these noises reach a certain level, you must use other network equipment that allows the regeneration of the original signal. As this equipment will introduce delays in the network and also increase the cost of it, this level should be well studied by the network designer.
Optical multiplexers (add-drop multiplexers)
The terminal multiplexers are not the only multiplexer on a fiber optic network. Just imagine what would happen if it was necessary to add a terminal multiplexer on the way of an optical fiber.
While the terminal multiplexers work with the system tips, inserting information that will travel on the network from one end to another, the add-drop multiplexer inserts and removes the network information for your route, which allows the inclusion of more multiplexers terminal network, thus broadening its scope.
These devices also allow the transmission medium is shared by other equipment, thereby forming a topology bar (or ring, as it is more commonly used) and reducing the cost of deploying such technology.
Optical Cross-Connection Equipment
As in conventional networks, fiber-optic network also has routers. These devices allow interconnection of two distinct networks with a view to traffic information from one network to another.The significance here is that terminal equipment do routing between fiber optic networks for twisted pair, but only the cross-connect optical equipment does this between optical networks.
In addition he works with all wavelengths, different add-drop multiplexers of working with one. Because of this, need to have a large information processing capacity or will enter a large delay in the network and will be much more expensive than other equipment.