iPhone: The Missing Manual, 2nd Edition

Phone

These settings have to do with your address book, call management, and other phone-related preferences.

• International Assist. When this option is turned on, and when you're dialing from another country, the iPhone automatically adds the proper country codes when dialing U.S. numbers.

• Call Forwarding. Tap to open the Call Forwarding screen, where you can turn this feature on or off. See Call Forwarding for details.

• Call Waiting. Call Waiting, of course, is the feature that produces an audible beep, when you're on a phone call, to let you know that someone else is calling you. (Call Waiting has details on how to handle such a traffic jam.)

  If Call Waiting is turned off, then such incoming calls go directly to voicemail.

• Show My Caller ID. Ordinarily, other people can see who's calling even before they answer the phone, thanks to the Caller ID display on their cellphones or some landline phones. If you'd feel more private by hiding your own number, so people don't know who's calling until they answer your call, turn this feature off.

• TTY. A TTY (teletype) machine lets people with hearing or speaking difficulties use a telephone—by typing back and forth, or sometimes with the assistance of a human TTY operator who transcribes what the other person is saying. When you turn this iPhone option on, you can use the iPhone with a TTY machine, if you buy the little $20 iPhone TTY adapter from Apple.

• SIM PIN. As noted on SIM Card Slot, your SIM card stores all your account information. SIM cards ...