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4/8/2010

Connection Manager supports cellular networks that have simultaneous voice and data enabled. Support for simultaneous voice and data starts when Connection Manager receives from the Radio Interface Layer (RIL) a RIL_NOTIFY_SYSTEMCAPSCHANGEDnotification with the lpDataparameter pointing to RIL_SYSTEMCAPS_VOICEDATA. Connection Manager stops supporting simultaneous voice and data if this RIL notification is not received.

A network has simultaneous voice and data when a data connection can transmit data while a voice call is in progress. This differs from suspend and resume functionality which suspends the data connection during a voice call and no data is transmitted.

If the network does not support simultaneous voice and data connections, Connection Manager disables the data connection when a voice call is active, or suspends the data connection if the connection is marked as suspend and resume capable in the registry.

Simultaneous voice and data applies only to networks that have separate infrastructures for handling voice and data. Networks that do not differentiate between voice and data, for example Wi-Fi, do not have to support simultaneous voice and data. Newer cellular networks, for example 3G networks that support W-CDMA, are simultaneous voice and data enabled.

See Also