With Google Voice, you can now make calls using Hangouts, even without having a Google+ account.
The news was announced through the company’s social network, stating that the feature still works even if you are not using Hangout in Gmail. So, to use this feature, when in Google Voice, select Hangouts from a drop down menu tagged “phone to call with”. A seperate Hangout window will be launched, then you continue your conversation.
Hangouts is Google’s own messaging application. But of recent they have been incorporating other features like calling and Photo messaging to make it an all in one app for communicating. And they haven’t done badly.