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Does using code #3370# really help boost your cell phone signal?

Nov 02, 2018

Does using code #3370# really help boost your cell phone signal?

DIY Signal Boosting Series - Secret Phone Code #3370#

Some DIY cell phone signal booster tricks can provide some minor improvements, but as we see with secret codes, they are not legitimate cell phone signal solutions.

Getting in on the secret: Smartphone codes not all they are cracked up to be.

An email entitled "Five Things You Never Knew Your Cell Phone Could Do" has been making the rounds for some time now, forwarded on by well-meaning friends and family. The email makes several claims, ranging from the misunderstood to the outright goofy, including suggesting you can use secret phone codes to increase your battery life or improve your cell phone signal. Today we will explore the myth of dialing  #3370# and provide you with a few DIY cell phone signal booster tips.

What is #3370# supposed to do?

According to that email, pressing #3370# allows you to access a hidden reserve of battery power, so that when you restart "the instrument will show a 50 percent increase in battery" and this reserve will recharge the next time you start your phone.

Okay, that seems... unlikely. Nonetheless, this tip has been shared so many times it has become considered widespread "knowledge". As the myth grew, it mutated slightly on cell phone forums and social media platforms to claim #3370# is one of the secret phone codes designed to boost cell reception. If this seems like it is too good to be true, that is because it is!

What's really going on?

There're several levels of misconception to unpack here. To make some sense of the first claim that #3370# extends your phone's battery life - We found that the hidden battery power claim originates with an option on Nokia and some other phone brands called Half Rate Codex. Half Rate Codex provides approximately thirty percent more talk time on a phone battery by reducing the sound quality. That is great if you need to extend your battery... except #3370# isn't the right code to perform that function!

Instead, #3370# or *3370# enables Enhanced Full Rate Codex, improving sound quality at the expense of battery life - which you will recognize as the exact opposite of what the myth claims the code does. The real code for improving battery life by reducing sound quality on some phones is actually *#4720#. In reality, this trick on how to improve cell phone signal is contradictory and confusing when it comes to extending the battery life of your smartphone.

So, can #3370# boost cell reception?

We have seen that this secret phone code is less than ideal when it comes to extending battery life, but what we really want to know is if it is a reliable DIY cell phone signal booster option. Again, the answer is no. When #3370# activates Enhanced Full Rate Codex, the signal can seem stronger because the quality of the sound goes up, but this does not lower the chance of your call being dropped due to poor reception. Activating Half Rate Codex may boost cell reception slightly, as your battery needs a certain amount of charge to find a cell signal. Any slight improvement that you may notice will be short-lived though as the quality of your calls will begin to decrease as the better drains again. So clearly, this little trick is should not be seen as a legitimate long-term solution to improving your cell phone's signal strength.

Accurately judging your cell phone signal.

So if there aren't any secret phone codes to boost cell reception, what can you do to get a better signal? For that matter, what is considered a strong cell signal?

If you judge your cell phone signal by the number of bars in your phone, we have got some bad news for you. The cell phone industry does not have a standard unit of measurement for cell phone bars. This means you could have one bar, your friend with a different cell phone brand could have three, and yet you're both receiving the same signal strength. So how do you know what your cell phone signal strength actually is, if the bars do not really mean anything?

A more accurate way to evaluate your cell phone signal is to set the phone to Field Test Mode, which displays the signal strength in dBm (decibels below 1 milliwatt). To activate Field Test Mode on an iPhone, dial *3001#12345#. On an Android, open "Settings", click "About", then click "Settings", which will display the signal strength option or see the guide at link above to see other possible variations in Androids. This feature will provide you with the specific details that you need to ensure that your phone is operating at an optimal level.

Don't be alarmed if your field test provides a negative result. -70 dBm or better indicates a strong signal. -100 dBm or lower indicates a cell signal dead zone. If you find that your smartphone is consistently showing a poor signal strength, be sure to review all of your signal boosting options using our buy cell phone booster tool.

DIY cell phone signal booster tips.

Your best option for boosting cellular signal indoors whether home or office, is whole home/office cell phone booster or a vehicle-based automotive cell phone booster. These options make it easy for you to keep connected whether you are staying put or are on-the-go. If these choices aren't available, see few more DIY cell phone signal booster tips that might help alleviate your poor signal strength, depending on your location.

  • Move into an open space. Cell phone signals can be blocked or reflected by a variety of obstructions. Ideally, you want a clear line of sight between you and a phone tower, but failing this seek out as open an area as possible.
  • Toggle airplane mode on and off. Turn airplane mode on, wait three seconds, then turn airplane mode back off. This reboots your signal, which hopefully connects you more quickly to a cell phone tower in closer proximity.
  • Avoid other electronics. Laptops, microwaves, tablets, and other electronics can all interfere with cell phone connections. Moving away from such devices or turning them off may improve your signal.
  • Turn off Wi-Fi and Bluetooth. Wifi and Bluetooth consume your phone's available resources. Turning them off conserves battery power, which you may need to find a signal.
  • Keep your battery charged. Cell phones use more power when they connect to a network than they do in standby mode. If your battery is too low, the phone may not have enough charge to find a signal.
  • Hold your Phone upright. Holding your phone upside down, on its side, or in other strange positions can interfere with the device's antenna, which sends and receives the best signal when held upright. An exception does exist with newer models of phones, which have the antenna at the bottom of the phone. With such phones holding the device upside down can sometimes boost the signal.

It cannot be stressed enough that the most effective method of improving cell reception is to use a signal amplifier or repeater. While there are some DIY hacks that temporarily improve signal strength, none of these solutions provides a long-term, reliable increase in your cell phone reception in your location whether car or office building is blocking wireless signals to most spaces inside. provides Wi-Fi and cell phone signal boosters for all environments, from the comfort of your own home to backroads fifty miles from the nearest cell phone tower. As for secret phone codes, it really doesn't make sense that a phone manufacturer would deliberately hide options to improve reception. After all, they want us to use their products.

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  • Years ago it used to give you access to the last 30% of the battery, example. Actual reading say at <5%, punch in the code, it would run then ask you if you wanted to run this code warning that it degraded the overall battery life. Press OK now screen would read <35%. Consider it a hidden level. Tried the code in my new phone it is a no go, guess they took the feature out with improved battery design. It had nothing to do with boosting signal strength, although those days were the CDMA days where cell phones worked over long distances…

    Alan on
  • Some people will believe anything. If there was a secret code that actually boosted your battery, why wouldn’t cell phone manufacturers tell you? It goes against any kind of common sense to think a magic code is going to improve your signal. I’ll stop here before I say anything nasty about people who believe this.

    Kimberly Sullivan on
  • Bluetooth takes a lot less power than cell.
    Cell takes a lot less than wifi.
    Wi-Fi takes much less than lit screen.
    Battery level has zero impact on the ability of any feature to work – 90% of the total power runs through switching regulators that have typically <1% tolerance.
    Please verify your engineering claims with an engineer.

    Hans Schulze on
  • #3370# or *3370# only says “Connection problem or invalid MMI Code.” It doesn’t really do anything.

    Hansel Salvo on
  • When I read someone say, “*3370# not working!” I wonder if their brain is working. There are ways to help strengthen/boost your cell signal, but typing in a secret code is not one of them. Check around and you’ll find ones that work such as switching from airplane mode back to normal mode.

    Bobby Wilder on
  • I’ve seen some weird solutions for how to increase signal strength on an Android phone, but this is a new one to me. My favorite used to be those stupid stickers that are supposed to increase your phone’s signal strength but do nothing. This one has to take the cake. You type in #3370 on your Android and your phone magically gets a boost in reception? I guess some people will fall for anything when it comes to the ever-present problem of dropped calls, lousy voice quality, and slow as molasses data speed. This is one of the funniest things I’ve read about in a long time and should qualify as one of the craziest tech urban legends.

    Piotr R. on

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