There are two different calling modes that can be used to make and receive phone calls with the Ooma Office mobile app:

VoIP mode

VoIP stands for Voice over Internet Protocol. Use this option if your phone is connected to a strong, reliable, and cost-effective Internet connection.


  • Using VoIP allows you to use call control features like hold music and call transfer.
  • VoIP can be a less expensive option in some cases. For example, you can use a free Wi-Fi connection to make free calls when you’re traveling internationally.


  • If you are not connected to Wi-Fi, VoIP calls will use 3G/4G/LTE data from your cellular carrier.
  • VoIP calls on cellular data (3G/4G/LTE) may be less reliable, especially while you’re in motion, like if you’re driving or riding a bike

Cellular mode

Use this option for greater reliability when making and receiving calls, especially if you’re in the car or otherwise in motion. Instead of making calls over the Internet, the app uses your standard cellular voice minutes.


  • Superior performance while you’re driving or otherwise active.
  • Works better when your 3G/4G/LTE or Wi-Fi connection is slow or unstable.
  • May cost less than using cellular data.


  • Many modern cellular voice plans have unlimited minutes, but this mode will consume minutes from cellular plans that are not unlimited.
  • Does not provide in-call features such as hold music and call transfer.
  • Requires additional initial setup.

The first time you place an outgoing call in Cellular mode, you will see a popup that contains additional information about this calling mode. Tap “Continue” to continue seeing this popup for subsequent calls. Tap “Don’t show again” to permanently dismiss the message.

When a call comes in via Cellular mode, your phone will notify you before it rings. Your phone will ring a moment later. Depending on your preferences, you may hear an automated prompt asking you to press 1 to accept the Ooma Office call.

Changing your calling mode

If you don’t choose a calling mode, your app will default to VoIP mode. You can change your calling mode at any time by following these instructions:

  1. Log into the mobile app.
  2. Tap the More tab, then tap Preferences (iOS) or tap Preferences in the settings menu and choose Calling Mode (Android).
  3. Toggle your app’s calling mode.
  4. Tap Save.

If you are switching from VoIP to Cellular mode, you will need to enter your 10-digit cellular number.