Your Android device holds a large amount of information about its hardware and system that an average user might find difficult to access. But if you know Android's secret codes, you can factory reset your device, find out its hidden camera information, instantly back up your precious data and much more.
Some 'secret' codes are Android system codes, and usually begin with an asterisk or a pound symbol/hashtag. These don't require you to be connected to a network to use them, since they're just for the Android system on your device. These codes are updated regularly as new versions of Android software are released, and some manufacturers have their own additional special codes.
The code entry procedure is very simple and only requires you to bring up your dialer keypad and enter the appropriate number sequence. It's important to note that some codes are carrier-specific, so they won't work on all devices.So if your phone doesn't respond to a code, don't dwell on it, just move on and find another one.
Warning! These codes should be used with caution. They can make your phone lose data, or render it unusable. There's a lot of incomprehensible tech jargon which pops up in the menus after entering some of these codes, which means that if you aren't 100 percent sure what you're doing, don't do it.
These codes are mostly universal, and should work on Android devices, no matter the manufacturer. There might still be carrier restrictions on certain codes though, so they're not all guaranteed to work.
These aren't the secret ones, but they're not so well known. USSD, or Unstructured Supplementary Service Data, codes connect to the phone's network once dialed to perform certain functions, like finding out how much credit you have left on your prepaid phone or how much data you've used this month. They change often, and the codes vary from carrier to carrier. Here are a few you can try for some of the major US carriers, along with links to more carrier-specific codes: