Enable Field Test mode on mobile phones

When most people talk about cell phone signal strength, they talk about “bars” in reference to the signal strength bar indicator on the phone. While bars are an easy way to talk about signal strength, it turns out that it’s not a very accurate way.

This is something I try to turn on on my iPhone (scroll down to "Always show Decibels instead of Dots") whenever I can, as I find dots very vague.