Do you need an ONT? Know the best ones to replace the operator’s router

What is an ONT and what is it for?

The ONT or also known as Optical Node Terminal, is the device that connects to the end user, that is, at the customer’s home, to connect to the GPON or XGS-PON network of the operator in question. The objective of an ONT is to provide the conversion of optical signal into electrical signal, providing Ethernet output with RJ-45 connector, to later use a neutral router that will establish the connection to the Internet. An ONT is nothing more than a device that has fiber optic input, with the typical SC connector that connects from the PTRO (Optical Network Terminal Point) to the ONT itself through the single-mode fiber cable that is normally colored. yellow, although there is also white.

The ONT is a link layer device, it takes care of communicate with the OLT (Optical Line Terminal) that is in the operator’s central, and let us pass for the connection. ONTs must authenticate against the operator’s OLT to allow it to send and receive data. Depending on the operator, different authentication modes are used. For example, with Movistar we only need to know the IDONT that they have installed in the default router, however, other operators such as Grupo Masmóvil need an «ONT password», that is, a password for authentication that the installer generally does not provide us this information, nor the operator itself.

Having an ONT is completely necessary if we want to connect to the GPON or XGS-PON fiber optic network of the operator. The problem is that most operators that use direct coverage use routers with integrated ONT, and in many cases the firmware allows us to configure it in bridge mode to later configure a neutral router with the Gigabit or Multigigabit Internet WAN. This is a problem because we would have double NAT, and if you are thinking of buying your own router, it is very important that the public IP address is the neutral router and not that of the operator.

How do I know which ONT is the best for my connection?

If you are interested in buying an ONT and using it with your operator, you should know that not anyone will do. Although all operators comply with the GPON or XGS-PON standard, and also the ONTs that we can buy anywhere, the truth is that we depend on several factors to make them compatible, especially when managing authentication with the OLT of the operator. There are some ONTs that do not allow you to configure IDONT, or that simply are not able to authenticate correctly against the OLT, so this ONT will not work for you.

The most important recommendation that we are going to make from RedesZone is that buy an ONT that the carrier has previously used on their network. For example, Movistar has been using the Huawei HG8240 and Huawei HG8240H as ONTs for its Internet connections for many years. If you want to replace the operator’s HGU router and buy an ONT to have a full-bridge and use your own neutral router, the best thing you can do is buy one of the “old” ONTs in the second-hand market, to make sure 100% that it will work correctly. The same happens with other operators, it is highly recommended to get an ONT (brand and model) that they have used previously, and if it is second-hand that has already been used in the operator in question, the better, because we will make sure that the firmware it is perfectly compatible with the operator’s OLT.

When you buy an ONT, you should know that the operator is not going to provide you with any kind of support, so you must make sure that you will be able to use this new ONT and that you will not have problems with authentication or compatibility. It is very important that you previously investigate how to replace the ONT of your operator, the simplest is Movistar / O2 since the IDONT can be copied directly from the router when it is in installation mode, however, other operators make this task really complicated, and even outright impossible if you don’t have an ONT password that you must use.

Once you know for sure that you can buy an ONT because you have the IDONT data and / or password for authentication, you have to see what ONT we have available in the market.

Fiber ONT for use with your operator

You can currently buy all the ONTs that we are going to indicate below, some of them are the “free” version of the same model that has been used by Internet operators in Spain for years, so they should be compatible and that there is no problem. We will also make some comments about the different ONT models so that you know if it is compatible or not.

Ubiquiti UFiber Loco

This ONT is one of the best-selling and most recommended, because it has a really good compatibility with the different operators, especially with Movistar. This model is capable of providing you with a symmetric 1Gbps speed in the Movistar network without any problem, according to the comments of several users through the forums. This model is compatible with the Movistar / O2 network, although you must bear in mind that, if you have IPTV with Movistar TV, you will not be able to use this ONT at the moment, because it seems that it has problems when managing the multicast traffic that reaches it. , so you will not be able to use this feature.

If you have the Movistar / O2 operator and you want an ONT for the Internet and VoIP connection, this model is one of the best you can buy, and it is perfectly compatible with this operator, except for the TV part as we have indicated, although it is It may be that in future firmware revisions it will work correctly. Currently on the Internet there are many tutorials on how to configure this ONT so interesting for the blue operator.

This ONT has several profiles that are adapted to different brands that operators have been using. For example, profile number 2 refers to Huawei’s ONTs, for this reason it is ideal for Movistar / O2 and also for any connection through NEBA. Profile 4 refers to the manufacturer ZTE, so it would be compatible with Orange, Jazztel or Digi.

ZTE F601

This is one of the most popular ONTs for Orange and Jazztel operators, it is one of the best options in terms of quality / price and also size, because it is a really small device. ZTE has been on the Orange / Jazztel network for many years and this particular ONT has been in use for many years, so if you can get hold of the “free” model, it should work fine for you.

ONT ZTE F601As we have indicated before, our recommendation is that you buy second-hand ONTs that users have tested in the operators and it works for them, because we depend on many external factors that will make them not work correctly. The price of this ONT is around 20 euros approximately, so it is worth a try.


This model is quite inexpensive and is available in stores like Landashop for less than 20 euros, a price that is also very competitive. This ONT is very basic but it will allow us to connect to the operator’s network, however, before buying this model you should read and ask the store directly which operators have tested it, in order not to err in the attempt to change the ONT of the operator by this model.


As you have seen, we currently have few options in terms of ONT available in the market, the main problem is due to the operators, due to their form of authentication and compatibility.

The best ONT you can buy is one that has previously been used by a user and has put their experience on the Internet, to highlight the Ubiquiti ONT that has several profiles and gives us a very good compatibility, in fact, there are very good comments about this device through the different forums, especially if you have Movistar / O2.

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