iPhone: Understanding phone features

Summary

Certain phone features on iPhone behave differently on GSM and CDMA networks.

Products Affected

iPhone

iPhone supports many phone features, including call waiting, call forwarding, and conference calls.

There are different methods for enabling and using the following features, depending on your wireless carrier's network technology (GSM or CDMA):

Call forwarding Turn on or off in Settings > Phone Contact your carrier for information on using Call Forwarding  
Call waiting Turn on or off in Settings > Phone Contact your carrier for information on using Call Waiting  
Caller ID Turn on or off in Settings > Phone Contact your carrier for information on using Caller ID  
Conference calls Supports up to five calls simultaneously Supports up to two calls simultaneously. CDMA networks may not be able to add, swap, or merge calls in certain situations. See the iPhone User Guide for more details.
Dial a soft pause Tap and hold * when dialing. When editing a contact number, tap +*# and then tap "pause".  Inserts "," into a phone number. Waits a few seconds before dialing additional digits.
Dial a hard pause* Tap and hold # when dialing. When editing a contact number, tap +*# and then tap "wait". Inserts ";" into a phone number. Waits for the user to tap Dial before dialing the additional digits entered after ";".
Place a call on hold Tap and hold Mute N/A CDMA networks do not offer the ability to place a call on hold.
* Requires iOS 4.3 or later.

Note: For information on differences when using cellular data networks, including LTE, see this article.

Additional Information

When using an iPhone on a CDMA network, you may notice the following differences:

  • Contacts or phone numbers on webpages that contain alphabetic characters beyond seven digits may not dial as expected. Example: 1-800-MY-IPHONE or 555-1212x1234.
    • In these instances, either remove the additional letters or use a pause to dial the extension (555-1212,1234).
  • The following settings and features may not be available on iPhone on CDMA networks:
    • Enabling a SIM PIN
    • Importing SIM contacts
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