google talk android device sign is not shown by sony xperia ray while logged in google talk in it what can I do about it?
Launch the Google Talk app
Open the overflow menu (three vertical dots) and choose Settings. 
Tap the account you're using. 
Check the Mobile indicator option.


Note: If you're signed in to your Google account on a PC (like if you left your browser open and logged in to Gmail) the mobile indicator may not be displayed.

(For reference: Android version 4.1.1, Google Talk v. 4.1.1 - 424425)