iPhone: The Missing Manual, 2nd Edition

Wi-Fi

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

• Wi-Fi On/Off. If you don't plan to use Wi-Fi, 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.

  Note

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

• Choose a Network. Here, you'll find a list of all nearby Wi-Fi 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 Wi-Fi networks that are invisible and secret unless you know their names. See Chapter 6 for details on using Wi-Fi 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 Wi-Fi 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 Wi-Fi networks, which can happen in heavily populated areas, and to save battery power.