What does it mean when the red light of LOS is always on but not flashing? It's not the same disease as flash red. It took my mother-in-law's house a whole night to figure it out.

Last fall, my mother-in-law's house was disconnected from the Internet. The old lady described it very clearly on the phone.: 「The red light on the cat doesn't flash, it just stays on. 」I was at work at the time, so I casually said, "Restart it and try it." After restarting, it was still on. I asked her to unplug the fiber optic cable and plug it in again, but it still turned on. My heart skipped a beat - if it flashed, the problem would be less ； If it stays on, it probably doesn't happen at home.

Later, the master came to the door and checked from the end of the corridor's spectrometer, and found that the core of the leather cord was broken by rats in the corridor shaft. Twenty minutes after the line change, the LOS went out and the network came back. After this trip, I completely understood the difference between "constantly on" and "flickering". These are two completely different diseases, and the treatment paths are also very different. I was before LOS red light flashing troubleshooting In that article, I wrote about the main line of flashing, but this article specifically talks about the constant light.

First separate the two types of red lights: Flashing means "sometimes good and sometimes bad", and constant light means "not at all".」

LOS is a light that only cares about one thing: Did the optical modem receive the light? The name when broken down is Loss of Signal, the signal is lost. It does not owe fees, does not check passwords, and does not care about your home router. It only detects whether there is light coming in from the yellow cord that enters the door.

Flashing red is the light jumping repeatedly across the edge of the threshold. . When the light is weak near the critical value, the cat can receive it for a while and cannot receive it for a while, and the light will flicker on and off accordingly. Your home can still be connected to the Internet intermittently, or it may be disconnected at night and come back to life during the day. This kind of "good and bad" disease is mostly caused by excessive light attenuation, a dark bend in the wire, and dirty connectors. There is still hope for your home. You can often recover a few dB by smoothing the wires.

It's always bright, but the light can't get in at all. . If the received optical power continues to be lower than the lowest threshold that a cat can detect, it is not shaking, it is not happening. In this case, the leather cord is most likely physically broken - the core wire is broken, the connector falls off, there is a problem at the end of the optical splitter, or the port is turned off in the computer room. It's useless if you wipe the joints a hundred times at home, because the light never reaches your house.

What delayed my mother-in-law the most that night was my words of "try to restart." Restarting is of no use to keeping the LOS always on - the light is not coming in, even if the cat restarts 10,000 times, it still won't receive it. It is not like a soft fault like flashing red. It can sometimes be restored after powering off for a minute and then on again. Always on is mandatory, so put aside the idea of ​​restarting it first.

Don’t be in a hurry to make a call when the light is on. Go through the three-step positioning method first.

Although the repair basically depends on the master, the positioning work done before you call directly determines whether the master will "fix it in one visit" or "make two trips back and forth." I later helped two neighbors deal with the same constant light problem, and they both spent ten minutes doing these three steps first.

The first step is to see what the PON lamp is doing. When the LOS is always on, the PON is probably off - it cannot be registered without light. But there is an exception: The PON red light is always on. Some models of cats will also display "Registration Rejected" as a red light. In this case, it may be a good idea to turn off the light, because the computer room did not recognize you (the SN is not bound or the port data is lost). Looking at the two lights facing each other can first separate "the light path is broken" and "the registration layer has an accident". The complete comparison of lantern language is here Indicator Dictionary There was a table written in that article.

The second step is to ask your neighbors. The same optical splitter in the same building is also broken at the neighbor's house. That is the pot between the optical splitter and the computer room. It has nothing to do with your home's electrical wiring. Just call for repair and say "several households in our building are broken." The neighbor's house is fine, so you need to check your own house.

The third step is to follow the yellow leather line from beginning to end. Start from the connector on the back of the optical modem and touch all the way to the wall hole entering the house. Focus on three places: Is the connector loose (the small blue square head needs to hear a click before it is fully inserted) ； Are there any dead bends in the cable body (the bending radius of the optical fiber cannot be less than 5 cm) ； Are there any signs of the wall opening being pressed by furniture or being pinched by a door? If you feel obvious trauma, you will basically locate the crime scene.

If you can get in 192.168.2.1 In the background, look for the "Received Optical Power" column on the status page. If the number is below -30dBm or cannot be read at all, it is a real hammer that always lights up. How to find this number and how to view the binning? I'm here What to do if the light fades greatly The whole process is written here, including health within -27, low light from -28 to -30, and alarm outside -30. The binning table can be directly copied and used.

Three typical sources of constant light, ranked by probability

From the few times I have dealt with it and what the master said, there are basically three types of sources of LOS lights, ranked according to the probability of encountering them.:

first place: The leather cord is physically broken. The outer skin of the yellow leather cord that enters the house looks intact, but the glass core inside has been broken. There are usually three types of perpetrators: Rats gnaw (corridor wells in old communities are the hardest hit areas), decoration nails are driven to the thread, and there are also hidden injuries caused by being pinched by doors for a long time. My mother-in-law’s family is the first type. The characteristic of this type is that no obvious trauma can be found by touching the line, because the wound is in the corridor section that you cannot see. How to locate breakpoints, how to connect in emergencies, I’m here to take care of cold connections The fiber optic cable to the home is broken and I have to connect it myself. I did the math in that article - the conclusion is that it can be connected in an emergency, but in the long run you still have to change the line.

second place: The connector is loose or dirty. This accounts for a large proportion, and it is the only kind of permanent light that can be saved at home. It was loose due to cleaning, and the installer did not insert it properly last time, so the optical path was disconnected at the joint. Pull it out, wipe it clean, and plug it back in. If you hear a clicking sound, the LOS is off. So even if the judgment is "completely gone", the ten seconds of reinserting and wiping the head are still worth doing - just in case.

third place: Something went wrong with the optical splitter or the computer room. The optical splitter in the corridor was flooded, the port at the other end of the computer room was turned off, or there was a problem with the cutover. No matter how you check this, your home will always be clean. The characteristics are "the neighbor is also broken" or "the leather cord is intact but the optical power cannot be read". Don't do it by force, and don't buy the equipment and do it yourself. Call the computer room to check remotely. The master can see the status of your line at a glance in the background.

When you call for repair, why do you say that the technician will dispatch the order directly?

After the three-step positioning is completed, don’t put off the phone calls you should make. There won't be any miracle of self-healing if you stay in this state of constant light for a night - it's completely different from the "cutover in the middle of the night, and you'll be fine at dawn" in Flash Red. If the light doesn't come in, it doesn't come in.

There is something special about reporting for repairs: Don't just say "can't connect to the Internet", customer service will treat it as a normal failure and go through the process. Report the positioning results, a one-sentence template: 「The LOS red light of the optical modem is always on but does not flash. Restarting is ineffective. The optical fiber has been re-inserted. The received optical power in the background cannot be read (or is minus 30 or more). The neighbor's home is normal. 」So the customer service said that they would directly transfer the maintenance, and the master would immediately know that it was an issue with the optical path. He should bring a fiber splicing machine, he should check the optical splitter, and he would come to solve it in one visit.

My mother-in-law's time, I reported on the phone "LOS is always on, I have tried restarting and re-plugging, and the neighbor's house is fine." The master directly judged that the line at the home was disconnected, brought the line with him, and finished the work in 20 minutes. Later, the incident at the neighbor's house was smoother - I reported "the optical power could not be read". The technician first went to the corridor to take a look and found that the optical splitter connector was loose, and he repaired it without even entering my door.

There are still several links in the repair application process where it is easy to suffer hidden losses, such as how to urge the master if he does not come to the door for a long time, and how to accept the repair after it is completed. I am here Broadband repair process I wrote a complete set in that article, just follow the instructions and take two trips at a time.

Two situations where "it looks like it's always on" but don't panic

There is a kind of misjudgment that is easy to make: In the first few seconds after powering on the optical modem, LOS will light up and then turn off. That is a self-test process, not a malfunction. The judgment method is very simple - wait half a minute and look again. If it goes out, it will be fine. The complete waiting rules for flashing red (PON will flash for one to three minutes after an incoming call) are in this article PON light flashes during power outage I wrote in that there is a registration queue, so don’t sneak in.

The other is after factory reset. The light language that night when I pressed reset by mistake was "LOS flashes first, PON flashes next." It was the process of ITMS re-identifying the device. Don't cut off the power after half an hour. That is another story line. reset rescue There are full records. A real constant light doesn't have any of this foreplay - it just stays on steadily and doesn't move from the moment you notice it.

I still have something to confess: Don't take the LOS constant light as a sign that the optical modem is broken and you need to buy a new cat. If the light path is broken, changing the cat is equivalent to changing the soup without changing the medicine. If the new cat is plugged in, it will still light up, and the money will be wasted. The probability that the optical modem itself is bad is very low. The semantic meaning of the light always points to "line" rather than "cat". If you really have doubts about the cat itself, call for repair and ask the repairman to bring spare parts for replacement and verification. That is the most economical way. Thunder and Bad Cat It has been written that the operator will replace it for free.

ending: A decision card, follow it without detours

Compress the path of this article into a card, and deal with it in order when things happen.:

After that time at my mother-in-law’s house, the old lady summed it up herself, which I think is more concise than what I said.: 「Shem's disease is a disease in the home, and Liang's disease is a disease outside. 」The words are rough but the reasoning is not rough - Shen, there is still a possibility of saving the family. ； Always bright, leave it to the master if the positioning is clear. The time you have to look back at this article now is probably enough time to complete the three-step positioning and make the phone call. Regarding the light path, the sooner you report it for repair, the sooner it will be back online. If you wait, there will really be no improvement.