Dial *3001#12345#* and press the Call button. This will launch the Field Test Mode app and where the bars/dots were in the top left corner of the screen, you'll now see a negative number. The negative number is the decibel signal strength reading and should be followed by the carrier name and then the network type.
*3001#12345#* followed by the Call button. This should take you to the field test display and give you several options such as your SIM info, serving cell measurements, and your connected mode. Once in this mode, follow the steps below to find the most relevant information to your signal strength.
Accessing Field Test Mode on an iPhone can be quite straightforward: simply go to your phone's dialer, type in *3001#12345#* and hit the dial button. Unfortunately, though, you often can't get reliable signal strength (RSRP) or signal quality (SINR) readings on iPhones.
Open phone app and dial *3001#12345#* Tap Nr Reach Attempt under 5G to measure 5G signals. Tap Reach Attempt under LTE to measure 4G signal (RSRQ/SINR not available) RSRP value represents signal strength.
*3001#12345#
This secret code allows your phone to enter a so-called 'Field Test Mode' and gives you precise data on how strong your signal strength really is. While signal bars have always given us assurance that our phone signal's just fine, the truth is, information displayed on these bars are often inaccurate.
If you want to hide the caller ID dial *31# and press call button. This code allows you to check which number your phone is currently forwarding calls to when you're busy or reject a call. If you want to deactivate call waiting dial #43#.
By pressing *3370# or #3370#, you'll activate your phone's “reserve battery power”. Battery life will increase by 50%. The reserve will automatically charge up the next time you change your device.
To enter Field Test mode, open the Phone app and dial *3001#12345#* on the keypad. Yes, really. We weren't kidding about this being a truly hidden trick! Hit the call button, and Field Test will start up.
The number you see displayed for the rsrp0 in field test mode is a measurement in decibel milliwatts. It's a negative number that should fall between -40 and -130. The closer this number is to zero, the stronger the signal, so a signal strength of -60 dBm is stronger than -80 dBm.
What does dialing *#21# actually do? When you dial *#21#, you are, in fact, activating a feature access code that quickly tells you the status of call forwarding for your phone. It's a quick way of seeing what, in the case of this particular 'setting interrogation code,' your call forwarding settings.
From iPhone Development Wiki. Private frameworks are frameworks which Apple intends for use only by Apple's own apps. Private frameworks are more unstable than public frameworks between iOS version updates, but many of the interesting features of iOS are in the private frameworks.
Android code: *#*#7262626#*#*
Knowing this is helpful in deciding whether or not to install a signal boosting system.
Code to check if phone is tapped: *#21# Code to show unknown connections and tracking (for Android): *#*#4636#*#* or *#*#197328640#*#*
The code #0# is a service mode code for Samsung Android phones. This code allows you to access various hardware tests and diagnostic tools on your device. By entering this code in the dial pad, you can test the functions of your phone's display, touch screen, camera, speaker, and other components.
1] On your Android device, open Settings and scroll down to the bottom. 2] Click on About Phone and select Status. 3] On the following screen, tap Network, and you'll be able to see signal strength for the SIM card operators on your device. It'll comprise of two numbers- dBm and ASU.
Visit sites privately
You can use Private Browsing Mode to open private tabs, which don't appear in History on iPhone or in the list of tabs on your other devices.
*#9900# Opens up system dump mode.
To check your voicemail, you need to select voicemail settings. Solution: Call 121 and follow the instructions to set up your voicemail.
*2767*3855# (Wipe Your Device and Reinstall Firmware)
Think of it as a factory reset—type this code on your dialer and run it, and it'll effectively delete all data from your phone, and wipe it clean.