15.2. WiFi

WiFi—wireless Internet networking—is one of the iPhone’s best features. This item in Settings opens the WiFi Networks screen, where you’ll find three useful controls:

• WiFi On/Off. If you don’t plan to use WiFi, turning it off gets you a lot more life out of each battery charge. Tap anywhere on this On/Off slider to change its status.

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  Note:

  Turning on Airplane mode automatically turns off the WiFi antenna—but you can turn WiFi back on. That’s handy when you’re in one of those rare, amazing airplanes with WiFi on board.

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• Choose a Network. Here you’ll find a list of all nearby WiFi networks that the iPhone can “see,” complete with a signal-strength indicator and a padlock icon if a password is required. An Other item lets you access WiFi networks that are invisible and secret unless you know their names. See Chapter 9 for details on using WiFi with the iPhone.

  
  

  

  
  

• Ask to Join Networks. If this option is On, then whenever you attempt to get online (to check email or the Web, for example), the iPhone sniffs around to find a WiFi network. If it finds one you haven’t used before, the iPhone invites you, with a small dialog box, to hop onto it.

  So why would you ever want to turn this feature off? To avoid getting bombarded with invitations to join WiFi networks, which can happen in heavily populated areas, and to save battery power. (The phone will still hop automatically onto hot spots it’s joined in the past.)