Ever wonder how much your mobile phone signal strength fluctuates? Or why you lose your connection when you head out for a weekend at your favorite summer getaway? With the simple trick detailed below, you can replace your cellular strength bar on your iPhone with a much more accurate numerical indicator and actually see what is going on with your cellular connection.
Like most smartphones, the iPhone uses a series of dots to indicate your cellular strength. It’s an approximation that provides a general overview of your current mobile phone connection. To get a closer look at your signal strength, you need to move beyond the circles and access the raw numbers that are used to generate this graphical representation. You can do this quickly and easily once you know how to open the hidden “Field Test” mode that provides details on your current cellular connection.
- Open the Phone app and access the dialer.
- Dial the following number, *3001#12345#* . Remember to include the asterisks and hashtags.
- Tap “Call” to initiate a call that’ll open Field Test mode.
Field test mode contains a wealth of information about your cellular signal. Most of this information is superfluous unless you are a technician trying to troubleshoot a cellular service issue. The one value that you are interested in is the negative number in the upper left-hand corner that replaced the signal indicator. This number is the power of your signal strength as measured in dBm units.
For most smartphones, the dBm of your signal will range from approximately -51 to -121, with a lower number representing a stronger connection. If your cellular signal reaches -130, then you will not be able to initiate a data connection or even make a phone call. This number is evaluated by iOS and used to generate the standard bar indicator, with -51 shown as five dots and -121 as one dot.
Under most circumstances, this strength value is available only when the field test mode app is open. As soon as you close the app, the strength bar and its imprecise circles will return. To keep the numerical display, you need to trick your iPhone into keeping this field test mode parameter open all the time using the following steps:
- Don’t press the home button to exit the field test app.
- Instead, hold down the iPhone’s power/sleep button until it shows the “Slide to power off” screen.
- Then hold the down your iPhone’s home button to force quit field test app.
You will return immediately to your iPhone’s home screen, but there will be a difference in what you see. Look closely at the upper left corner — the signal strength number has now replaced the signal strength dots . If you tap that number, you can quickly switch between the numerical value and the strength dots.
If for some reason you want to restore the signal strength dots and return to normal operation, just open the field test app again by dialling *3001#12345#* and use the home button to exit the app.