What is fiber, how does it work and what are its advantages over ADSL?


Optical fiber . The two buzzwords in the commercial offers of practically all operators. Until recently, fiber optics was not widely used, only offered by two companies. Now, however, practically all telecommunications companies offer some package with fiber. But what is fiber exactly? How does it work? Do we really need to install fiber optics instead of ADSL? We are going to try to explain, in words that we can all understand, what the fiber that the operators want to sell us at any price consists of and how it works.

Relax, our intention is not to make an explanation of how optical fiber works so technical that only a telecommunications engineer understands it. On the contrary, we want to explain, roughly, what that wonderful technology consists of that provides our homes with 300 Mbps connections that make us fly over the internet. The first thing we have to know is that we currently have two types of fiber available on the market: HFC and FTTH . The acronym HFC comes from Hybrid Fiber Coaxial or Coaxial Hybrid Fiber. In other words, although the operators sell it as a fiber optic connection, it really is a hybrid system between fiber optic and coaxial cable. Optical fiber is used to connect the main node to the nodes in each zone, but the cable that connects the node to the customer's home is a coaxial cable . Coaxial cable, for us to understand, is like the cable of a television antenna, but the one used is thicker and more rigid.

Coaxial cable

In an HFC installation, the installer will take the coaxial cable from the RITI (communications room of the building) or from the roof (if there is no RITI) to the customer's home. At home you will have to install coaxial cable to where we want to locate the cable modem (that's the name of the router that is put on this type of fiber). If we have hired television, you will also have to take the cable to the place where we want to put the decoder.

One of the best known operators in our country that uses this type of technology is ONO , or now Vodafone , since the British company acquired the cable company precisely to get its fiber network. Thus, the company currently offers HFCs in areas that already had ONO wired .

On the other hand we have the FTTH or Fiber To The Home system (Fiber to the home) . This system is used by Movistar , and now by the rest of the companies that are beginning to offer fiber, such as Orange or Jazztel . Vodafone also has part of its network with FTTH , but only in areas where ONO had not yet deployed cable. With the FTTH system , the fiber optic cables are brought to each customer's home, using optical distribution systems. Thus, all wiring, from the control panel (OLT)even our house is done using fiber optic cable. Once at home, the installer will upload the fiber cable from the RITI and will put an optical rosette on us . As a curious fact, the device used to fuse fiber optic cables is called a pigtail . Here you have a basic diagram of the installation carried out by Movistar .

Fiber Optic Installation

So what are the differences between HFC and FTTH ? At a technical level, the speeds that can be offered with FTTH technology are higher, but at the moment the maximum we have in the market are 300 Mbps connections, a speed that hybrid optical fiber (HFC) supports without problems. However, using coaxial cable can lead to further problems later, such as loss of power, cables being pinched by a staple, loss of signal, or misplaced connectors. There are also differences in the equipment that is installed. With the HFC system, access to the network is via a cable modem. The coaxial cable is connected to this equipment and it is in charge of modulating and demodulating the data signal. Currently, cable modems have a built-in WiFi router function , so it is possible to use a single device. If we hire television, the installer will have to put us a coaxial cable to the decoder , since in an HFC installation it does not connect to the router.

On the other hand, in an FTTH installation two pieces of equipment have to be used. On the one hand, from the optical rosette we will have a fiber cable that will be connected to a device called ONT (Optical Network Terminal) . The  ONT  is the device in charge of translating the optical signal into electrical and vice versa . It is an intermediary between the optical network and the WiFi router. In addition, it is necessary that it be connected to the electrical current. From the ONT we will have a network cable, the logical thing is that it is category 6, which will be connected to the WiFi router. If we hire television, unlike if we have HFC , the decoder will have to be connected to the router through a network cable, thus occupying one of the router's ethernet ports.

Advantages over ADSL

Optical fiber

The main advantage is obvious, speed . An ADSL connection offers a maximum speed of up to 20 megabytes . Very important to highlight the "to" , since the speed of an ADSL connection depends a lot on the distance from the central to our home . If we live more than a kilometer from the plant, the speed that will reach us will be much less than those 20 megabytes. On the other hand, when using copper cable, ADSLit is more prone to breakdowns or loss of quality of service. Fiber optic cable, on the other hand, is made of fiberglass and is specially designed to transmit large amounts of information. In addition, this type of cable does not suffer from interference problems or is affected by the distance from the control panel. That is, the fiber either goes or it doesn't (always talking about FTTH ).

Do we really need such a high internet speed?

It is a really difficult question to answer. The answer is: it depends . It depends on the use that we are going to give our internet connection. To be honest, most users will have enough with a working ADSL connection . We don't need a high-speed connection to surf the web, read email, and visit our social networks. If we want to watch movies or series in streaming, we will need more speed, although I can tell you that personally I use a rural connection of up to 10 megabytes and I watch Netflix in HD without cuts or stops. Online gaming is more demanding and if there are many of us at home and we all connect at the same time, ADSL could fall short.

Finally, it is necessary to comment that internet speed does not depend exclusively on our operator. We have to have some teams ready . In a rough way, if we contract a connection of more than 100 megabytes and we have a network card that is not gigabit, we will never obtain the maximum speed contracted. We must also assume that via WiFi it is very difficult for the full contracted speed to arrive, since this depends on many non-controllable external factors. In the article “ Is it worth installing 300 megawatt fiber? "We tell you what factors we must take into account to get the most out of our internet connection.