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.
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.
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.
Android code: *#*#7262626#*#*
Knowing this is helpful in deciding whether or not to install a signal boosting system.
Here's how to run an iPhone diagnostic test
With certain Android devices, you can dial in codes in the phone's app dialer — such as *#0*# and *#*#4636#*#* — to access a hidden diagnostic menu or usage information menu. You can also dial *#*#0*#*#* to test the LCD screen or *#*#2664#*#* for a touch-screen test.
Hide Your Phone From Caller ID: #31#
I could only get this to work on Android. But entering this code prompted a pop-up stating that my Caller ID had been disabled. In order to re-instate Caller ID, enter *31# .
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.
*#0*# - This will take you straight to the General Test Mode once dialed from the Phone app. It lets you test a bunch of things on your iPhone, such as vibration, touch, speaker etc. *5005*7672# - Dial this one up and you'll be presented with your SMS message center number.
Instead of tapping on the back of your phone or swiping a finger, this menu can be pulled up using the dialing pad. Here's how: Open the dialing pad as if you were making a phone call. Type *#0*#.
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.
To complete the cell phone signal booster installation process, connect the power cord to the amplifier and a wall outlet. It will take a few seconds for the booster to configure itself. Once it's done, the green lights on the booster mark the end of poor reception and dropped calls.
2. *#*#7780#*#* (Run a Factory Reset) If you don't want to run a hard reset, this is the next best thing. Similar to a factory reset, this code will simply delete all application data from your device, as well as any applications.
Call “##004#”
No one will answer when you call it, but it will turn off conditional forwarding on your phone. It will reset your phone to its default phone settings.
Code to check if phone is tapped: *#21# Code to show unknown connections and tracking (for Android): *#*#4636#*#* or *#*#197328640#*#* Code to show unknown connections and if someone is tracing you (for iPhone): *3001#12345#*
*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.
Call barring lets you block incoming or outgoing calls to and from your phone. This may be useful if you keep receiving unwanted telemarketer calls or want to avoid expensive international calls. To check if the feature is enabled on your device, dial *#33#. Use the code *33*pin# to enable call barring on your iPhone.