Your iPhone has secret ... and tap the call icon: *3001#12345#* The FTM Dashboard screen should appear with details about your carrier and your cellular signal. You can set up "call barring ...

An curved arrow pointing right. The bars on your iPhone actually represent a signal range, not an exact signal. Here's how to change it to the exact signal you're receiving at the moment.

Got a bad cell phone signal? Without a stable connection ... so give it a good 15 seconds before you tap on the Airplane mode icon again. iPhone: On the iPhone, you can access Airplane mode ...