In one embodiment, source data for a communication session may be split into an audio portion for transmission on a phone channel and a non-audio portion for transmission on a data channel. A server and a phone may accordingly establish an audio portion of a communication session on the phone channel. In response to a trigger, the server may provide a push notification on the data channel to the phone, where the push notification is associated with an application executing on the phone that is configured to participate in the non-audio portion of the communication session on the data channel with the server. Upon obtaining the push notification on the data channel during the audio portion on the phone channel, the application may correspondingly activate on the phone to participate in the non-audio portion of the communication session during the phone's participation in the audio portion (e.g., merging the portions).