Ah, the setting is "in the GV Android app".
I just realized that I have "Sprint Google Voice integration" turned on.
When I turned it off on the Google Voice website, I found the setting in the GV Android app.
Thanks for your help!
Ting.com does not have Google Voice Integration like Sprint does.
So, I was looking for a solution that allows me to call from my cell, BUT shows my Google Voice # on the caller id at the other end of the call.
Thanks again!