How to tell if the modem router is broken

All of a sudden our Internet line has stopped working, preventing us from continuing our work or blocking the viewing of the movie or TV series we were enjoying in streaming. Many times, understanding where the problem is could prove to be a difficult task, especially if the modem we use to establish the connection breaks.
Even if modern modems / routers are robust enough to withstand the most disparate situations, a blackout, a violent storm or other external factors (not least continuous downloads and uploads) may suffice to damage the logic board contained in the modem.
In this guide we will show you how to realize that the modem in use is broken by some signals (some easy to understand, others less easy) and in the case what to do to solve.

READ ALSO: Solve Internet and network connection problems on the PC

1) Check the LED lights

The modem can immediately provide us with information on the connection and its health by means of the LED indication lights on the front or top of it. The lights change according to the model, but you can still find directions by checking these 3 elements:

• Power light: shows that the modem is properly switched on and receives electricity; this light must be fixed and not flash.
• Connection light (ADSL, VDSL or Fiber): indicates that there is an actual connection between the modem and the telephone exchange (in jargon called carrier); this light must be fixed, otherwise there is a problem between the modem and the control panel (telephone cable or fiber optic cable, telephone socket, cabinet etc.).
• Line light (Internet): this light (not always present) indicates that we can connect to the Internet correctly; it must also be fixed.

To avoid confusion in modern modems it is joined together with the connection modem, becoming a single LED light for Internet connectivity. However, this concept is wrong, given that it can be a carrier but not surf the Internet, running the risk of not understanding what is wrong with the modem.

If we have to choose a new modem, then choose one that has a light for the connection and a light for the Internet, so as to immediately understand where the problem is present.

READ ALSO: Modem red LED (Internet absent): what to do before calling for assistance

2) Check the connection cable

After checking the modem lights the problem is the carrier?
In this case we will have to check the connection cable that goes from the wall socket to the modem, in the appropriate port (DSL, ADSL or VDSL, based on the technology in use).

Let’s try removing the cable and reinserting it, also eliminating any ADSL filters and connecting the cable directly; if you use VDSL connections, the filter is completely useless so we can remove it without problems.
If the modem is not navigating or still having problems, we can try to buy a new RJ11 telephone cable (6 €) or a new ADSL filter (3 €), if we still use this connection technology.

We don’t know the difference between ADSL, VDSL and optical fiber?
We advise you to investigate these terms in our detailed guide here -> VDSL, FTTC and FTTH fiber: which differences and which is better?

3) Check DNS parameters

Is the carrier present but the devices are not navigating or the Internet light is off?
In this case the problem does not concern the telephone exchange and the connection of our modem, but could concern the network infrastructure of our operator (problems on distribution lines or backbones). In this case there is little we can do but report the problem to telephone assistance; however, as a last resort we can change the DNS servers, one of the infrastructures used to browse the Internet correctly.

To change the DNS on PC we refer you to reading our dedicated guide -> If the DNS does not respond, how to resolve.
If instead we wanted to change the DNS on our smartphones or tablets, we refer you to reading the guide present here -> How to change DNS on Android and iPhone.

4) Check the Ethernet or wireless connection

Does the Internet work properly on another device on the network?
Then the problem could be one of the modem’s Ethernet ports or incorrect configuration of Wi-Fi connections.
If our device is connected via Ethernet cable, we can try one of the other similar ports on the back of the modem: if the connection is present, it means that the LAN port is defective or has some electrical problems (best avoided).

If the other ports are busy and we don’t know how to connect the device, we can always increase the number of ports using a working LAN port and connecting an Ethernet switch (€ 18).

If the device is connected via wireless, we must enter the modem configuration panel, take us to the menu Wireless and change the transmission channel for the 2.4 GHz frequency.

We choose one of the less crowded wireless channels, so as to minimize interference with nearby networks and other wireless devices. If our modem has a 5 GHz wireless connection, it is time to configure it and use it on devices that have a dual Wi-Fi module, so that you can surf the Internet using a faster and less susceptible to interference network.
To deepen the discussion on the differences between the two types of network, we refer you to reading our dedicated guide -> Differences between 2.4 GHz and 5 GHz Wi-Fi networks; which is better?

5) Conclusions

By carefully following all the steps described above, we will need to be able to understand if the modem router is faulty or has only a temporary problem, easily solved.
If none of the methods described above work, change modems or call for assistance it may be useful to completely reset the device: we identify the small hole with the word RESET (usually present in the back), insert a needle inside for about 10 seconds, then release it and observe the behavior of the modem.
With a little luck we could solve most of the software problems without even changing the modem.

If, on the other hand, our modem does not have 5 GHz connectivity, it will not work well despite the reset or it is damaged to the point of not allowing us to surf the Internet, we advise you to equip yourself with a last generation modem router, like those recommended in our guide -> Best WiFi Routers to connect wireless devices at home.