Nine checks. Tap the button, follow the two prompts, done in about a minute.
Results are sent back automatically.
Have the phone speaker on (not headphones, not silent mode) — two of the checks measure
what the microphone hears while the phone is talking.
Did you hear the beep?
Last one: tap below, then lock the screen for about 15 seconds, then unlock and come back
to this page. It records what iOS does to the microphone and the connection while the screen is
off — that decides whether the phone can sit on a table listening, or has to be held.