Many have experienced the need to visit a repair shop due to a malfunctioning smartphone. At the repair shop, we often encounter screens hidden on our smartphones. The repair shop person taps the screen a few times, and a screen we’ve never seen before appears on our phone. This is due to a “backdoor” preset on the phone. It is not the commonly used negative meaning of a backdoor, but a backdoor to deliver more accurate hidden information to the user. We call this the smartphone’s “secret code (assembly code).” We will introduce the secret codes of the two most widely used smartphones, Samsung Electronics’ Galaxy and Apple’s iPhone.
Check Galaxy Battery Temperature *#0228#
The temperature of a smartphone’s battery is extremely sensitive information. If the temperature of the phone’s battery remains high all the time, it can significantly affect the overall product and shorten the lifespan of each part. To prevent such a situation, here is a code to check the battery temperature of Samsung Electronics Galaxy brand smartphones. It may not work with third-party phone apps like T Phone, so input it into your smartphone’s basic call app if possible.
Galaxy Burn-in Test *#7353*#
Smartphone displays, prone to display the same screen for a long time, can easily experience “burn-in.” Burn-in is a phenomenon where the pixels of the display burn out, turning yellow or leaving permanent afterimages. Burning into a mobile phone display is only a matter of time, and it is inevitable. The secret code above displays various screens of primary colors, allowing users to identify areas where burn-in has occurred easily. However, this method can only be used up to the Android 9 version, and for the latest mobile phones, you must use ‘*#0&#’ instead of this code.
Galaxy Hardware Test Check Mode *#0&#
This secret code allows you to check the functions of the Galaxy smartphone’s hardware comprehensively. From the color expression of the display to vibration, camera, sensor, speaker, and hardware key response tests, most functions can be tested. However, the exposed items may vary depending on the product. S Pen testing is also possible for the Galaxy Note or Galaxy S Ultra series.
Galaxy Knockoff Distinguishing Code *#2663#
This code allows you to check the firmware information of the Galaxy smartphone. When the phone’s touch sensitivity is strange or literal, you can check the current smartphone firmware information. But there is another way to use it: to determine the “knockoff” of the Galaxy smartphone. It is almost impossible to find a Galaxy knockoff distributed in Korea, but if you have purchased a product through overseas direct purchase, it will be helpful to use this code once.
Galaxy Unique Feature and Serial Confirmation *#06#
Although it’s not common, there may occasionally be times when you need to check the product’s serial number, IMEI, etc. For some professions, including developers, this information, which people in other fields wouldn’t check, can be used effectively. *#06# is a code that allows you to check this quickly. After launching the Galaxy basic phone app and entering the secret code above, the serial number and IMEI appear in barcode form.
Find Out Galaxy’s First Call Day *#12580*369#
Imagine if you bought or received a Galaxy smartphone that someone else was using. They say they haven’t used it for long, but you can’t just believe that. If you want to guess how long the phone has been used, enter the secret code above. You can immediately check the AP and CP (modem), CSC (manufacturer software version), BL (bootloader), and “first call day” of the phone.
iPhone Calling Line Identification Restriction *23#
When we call someone, we assume the other person can confirm my phone number before receiving it. Interestingly, the iPhone has a secret code that can hide this. If you enter *23# and then make a call, the person receiving the call will see “Calling Line Identification Restriction.” This feature can also be turned on in the settings, but be aware that if you do, all calls to the other party will continue with calling line identification restriction until the feature is turned off again.
iPhone Call Waiting Setup Code *#43#
When I’m on a call, and someone calls me, a “busy” guide makes them wait until the call ends. Call waiting setup is a code that can be turned on through iPhone settings, but it also has a unique code that can set up waiting immediately. Also, if you enter *#21#, you can set all incoming calls to be redirected to a preset phone number. However, for this service, you may need to subscribe to an additional service depending on the mobile carrier.
iPhone Reception Sensitivity Check *3001#12345#*
There are times when the iPhone suddenly has poor call sensitivity. At such times, rather than suspecting a malfunction of the iPhone, you first need to check the network status of your current location. You will be taken to the field test window if you enter this somewhat long secret code and press the “call” button. Then, numbers appear on the left side of the screen. If this number is below -100, it can be seen that the reception sensitivity has weakened a lot.
iPhone EFR Activation *3370#
The iPhone’s EFR (Enhanced Full Rate) mode is activated when you enter this secret code and press the call button. This model is simply a “call quality enhancement mode,” when set, it can improve call quality. However, it can also drain the battery faster. Also, if you enter *#62#, you can check missed calls, and if you press the call button after entering *#36#, you can quickly check your device’s identification number, like a Galaxy smartphone.
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