Let's first analyze the communications system

Before starting to design a fiber optic cable network, it is necessary to determine together with the end-user or the owner of the network where the network will be built and what communication signals it will carry. Most contractors are familiar with internal plant networks, in which computer networks (local area networks or LANs) and security systems use structured cabling systems that are built based on well-defined industry standards. Once the wiring leaves the premises, even on short distance links such as a LAN network at the campus level or a metropolitan area network, the requirements for fiber and cable types vary. Long-distance links for telecommunications networks, CATV or utility companies have other stricter requirements that must be considered and are necessary to allow longer high-speed links.

However, although the contractor usually thinks first of the wiring requirements, the design itself begins with the analysis of the communications system requirements established by the end-user. First, attention should be paid to the types of equipment necessary for communication systems, the speed of the network and the distances it will cover, and then everything related to the cable network is analyzed. The equipment of the communications system will determine if fiber is needed or preferred and, in that case, what type of fiber.

Internal plant networks

Indoor wiring systems are designed to transport computer networks using Ethernet technology, which currently operates at a speed of between 10 megabits and 10 gigabits per second. Other systems can transport security systems with digital or analog video, perimeter alarms or access control systems, which generally operate at a low speed, at least as regards fiber. The telephony systems in the internal plant can be transported by means of twisted-pair cables or, what is more, common today, by means of LAN wiring with voice over IP (VoIP) technology.

In general, internal plant networks are short distance; They usually have less than 100 meters that are established as a limit for standardized structured cabling systems that allow the use of twisted-pair copper or fiber optic cabling. In turn, networks internal plant that is connected to a LAN at the campus level used in industrial complexes or institutions, have a backbone ( backbone ) that reaches a distance of 500 meters or more and uses fiber optics.

The networks in the internal plant usually operate with multimode fiber. Multimode systems are cheaper than single-mode systems. This is not because the fiber or cable is cheaper (they are not), but because the large core of the multimode fiber allows the use of LED or VCSEL sources in the transmitters, which lowers the cost of Electronic devices Often astute designers and end-users utilize both multimode fibers and single-mode in cable core network ( backbone ), called hybrid cables because the single-mode fibers are very economical and provide an almost unlimited possibility of expanding the systems.

External plant networks

Telephone networks are usually mainly external plant systems (OSP) that connect buildings both at short distances of a few hundred meters and at distances of hundreds of thousands of kilometers.

 In telecommunications, the data transmission rate is usually 2.5 to 10 gigabits per second, and very powerful lasers are used that only work on single-mode fibers. The tendency of telecommunications is to take the fiber directly to commercial buildings or homes since, at present, the signals are too fast for twisted-pair copper cables.

The CATV also uses single-mode fiber systems based on hybrid fiber-coaxial (HFC) or digital systems, in which the backbone ( backbone ) is fiber and the connection to the home is a coaxial cable. The coaxial cable is still used in the CATV since it has a large bandwidth. Some CATV providers discussed the possibility of taking fiber to homes or even tried, but the economic aspect still does not convince them.

In addition to telecommunications and CATV, there are many other applications of fiber in OSP. Smart highways are equipped with security cameras and signs and/or signals connected by means of fiber optics. Security control systems in large buildings, such as airports, commercial or government buildings, casinos, etc., are usually connected by fiber due to the large distances in these places. As in other networks, multimode fiber is usually used in internal plant installations, while single-mode fiber is used in the external plant to be able to make longer links.

Metropolitan area networks that belong to and are operated by cities can carry different types of traffic, including surveillance cameras, emergency services, education systems, telephone systems, LAN, security systems, supervision and control systems. transit and even, sometimes, the traffic of commercial interests when using a rented bandwidth that works by means of dark fibers or fibers that belong to the city. However, given that the majority of these networks are designed to allow longer links than internal or campus level facilities, single-mode fiber is the chosen one.

Fiber optic certification

For all installations, except in the internal plant, fiber is the chosen means of communication, since its capacity to allow greater distances and bandwidth position it as the only option or the one that is significantly less expensive compared to the cable Copper or wireless network. Only inside a building is the possibility to choose, and the economy, network architecture, and tradition of using copper cables in buildings influence that choice. Next, we will analyze in more detail the choice between fiber, copper and the wireless network.