From the CLI, "show voice call summary active" or "show voice call detail active"
From the GUI, Voice drop-down on the left, then Call Quality Stats button.
Alternatively, Monitoring drop-down then RTP Monitoring and click on the Active Calls tab.
I went ahead and flagged the "Correct Answer" on this post to make it more visible and help other members of the community find solutions more easily. If you don't feel like the answer I marked was correct, feel free to come back to this post and unmark it with the applicable buttons. If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.