When Google launched its new Unified Messaging service Hangouts We discovered that it did not have the integration of VoIP Google Voice and Gmail.com calls lost that functionality, but then Google reported that this integration would come in the future. As well, Google has already announced the launch of the calls in Hangouts, Although they will be available through Gmail.com, Google + web and its extension for Chrome currently only. For Android, it seems that we will have to wait.
The calls in Google Hangouts allows you to make and receive calls VoIP, but not only that, also we can add several phone numbers and participants of a same call video. Google stresses that Hangouts is designed to be the future of Google Voice, so we will continue seeing new features and improvements related to calls.
In the next few days the calls in Google Hangouts they will be available through Gmail.com, Google + web and its extension for Chrome, and as a novelty calls to USA and Canada will be free in all countries in which Hangouts are available. We hope that they will not take much to update the official Android app to add calls.