You might not think about your cell service indicators on a day to day basis, but in an emergency you need to know what they mean.
What Does It Mean When Your Phone Says SOS?
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How Many Bars?
One of the most well recognized service indicator icons is the image of bars you see on the top right corner of your phone. This particular icon is so well known that most cell service providers have developed slogans or ads around it. The number of bars you see is shorthand for how strong the service is in your area. No bars means you’ve got no service while full bars shows that you’re connected to a strong network.
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S.O.S.
Just because you don’t have regular cell service doesn’t mean you can’t reach emergency services. Your phone might display an SOS to indicate that, while your provider doesn’t have coverage in the area, your emergency calls will still go through. Since the phone won’t be able to connect to your main network, it will be picked up by whatever provider does have a network in the area instead. So, while you wouldn’t be able to call your friends or family, you would still be able to reach 911.
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Satellite
A satellite icon is the next step beyond the SOS. When you see this service indicator it means that your emergency calls will still go through. But they won’t be able to rely on a traditional network, since none are available. Instead, you’ll connect to the emergency services you’re trying to reach via satellite.
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Different “G” Variations
Many cellular carriers have advertised their 3G, 4G, and now 5G networks as a way to prove that they offer superior coverage. And all of these different networks means that there are several different service indicator icons to differentiate between them.
If you’re connected to a cellular network, then instead of the wi-fi rainbow in the upper right corner, you’ll see one of these “G” variations. 3G is older and slower than 4G, which in turn is older and slower than 5G, so even if you’ve got full bars you may still find that things connect slower on the older “G”s.
In some areas, carriers have slightly faster iterations of 5G available. If your phone connects to one of these networks, you’ll see it indicated by small letters or symbols immediately to the right of the 5G.
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LTE
Much like the “G” networks, most providers have something called a “long-term evolution” or LTE option. When it comes to speed, it sits slower than 5G but faster than 4G. You may see this one if you have an older model of phone that isn’t capable of connecting to 5G.
Source
Learn the meaning of the iPhone status icons, Apple Support.
