The BT Onevoice Mobile Access for Windows Phone application works in conjunction with BT's Onevoice Globally Managed Voice network. These application routes outgoing international IDD calls to a Onevoice gateway of that country where the call was made, and the gateway will connect the call through the managed network, delivering cost savings to the customer.

BT Onevoice Mobile Access is an end-to-end managed service that provides customers with the following compelling benefits:
- Reduced Long Distance Charges: Significant savings on International Direct dial calls to both Fixed and mobile phones.
- Global Reach: Available in 28+ countries (Europe, Asia and US)
- Onevoice Mobile Access facilitates a structured, phased approach for those customers who want to rationalize their mobile telephony strategy.