About SMS (text messages) in Google Chat
Gmail chat lets you easily send text messages to and from cell phones. If this feature isn't already enabled on your account, you can enable it by following these steps:
- Click the gear in the top right.
- Select Settings.
- Select the Labs tab.
- Scroll down until you see Text Messaging (SMS) in Chat, select Enable and Save Changes. You may also enable a supplementary lab called SMS in Chat gadget.
More about Gmail SMS chat: