You can receive Google+ Hangouts invites and voice calls (from one computer to another) in Chat. Just download the Google voice and video call plugin and sign into Chat to get started.
Whenever someone calls you in chat, youíll hear a sound notification and a chat window will appear. To answer a voice call, click the Answer button in the chat window or, click Join Hangout to accept your hangout invite. You can ignore the call by clicking the Ignore button.
If you miss your call, don't worry. The chat window will open, with a message saying who attempted to call you.