A PBX can receive a call for a mobile device, and can send a message over a data channel to the mobile device indicating such. The mobile device can open a voice channel for the call. The mobile device inspects information about the call, such as calling party information, and using historical information, such as statistics relating to acceptance of calls from that calling party to predict whether a user of the mobile device is likely to answer the call or not. If the mobile device predicts that the user is probably going to answer the call, then the mobile device begins establishing the voice channel before the user answers the call (e.g., by accepting through the user interface). However, if the mobile device predicts that the user is not going to answer the call, then the mobile device waits until the user actually answers the call to begin establishing the voice channel.