Look up at the top left corner of your iPhone… You see those little dots? As you should be aware by now, these dots are Apple’s way of representing something as complicated as a reception meter in a way a layman should understand. While this representation works for most users, it’s terribly inaccurate, and frankly doesn’t present much information.
What you may not be aware of however is that starting with iOS 4.1 Apple included a hidden app called “test app” that, when opened, enables a cool db meter where your traditional signal dots would be.
Jump over the break to learn how to enable numeric signal strength on your iPhone…
NOTE: even if the title says ‘iOS 9’, you can follow the same tutorial with ANY iPhone running iOS 4.1+
1. Open the Phone.app and tap on Keypad
2. Type *3001#12345#* and then tap on Call
3. As soon as you tap the Call button, the Field Test app will open. You’ll notice that instead of the standard reception dots in the upper left-hand corner of your screen, you’ve got a negative number indicating the decibels referenced to one milliwatt (dBm).
The problem is that, as soon as you tap that Home button to exit the Field Test app, your signal will be back to being displayed via the standard reception dots. So let’s see how to make the numeric display ‘stick’.
4. While in Test Field app, hold down the Sleep/Turn Off button until the Slide to power off screen comes up. Now, instead of turning the phone off, release the Sleep/Turn Off button and hold the Home button for a couple of seconds until it will return you to the Home Screen.
5. That’s it, now your signal will be displayed numerically. You can tap on it to switch between the numeric and dots display.
How to read the numeric display:
There’s a whole lot to say here, but let’s keep it simple:
- -50dBm: perfect reception
- anything greater than -100dBm: decent reception
- anything less than -110dBm: you pretty much have an expensive iPod Touch
For more info, check out this wikipedia page…