Hello Gary,
I don't believe that we have any documentation on configuring a PIN for international calls. Some carriers do not require / support that feature, but you will still want to check with your carrier if they can set up a PIN to be used for international calls.
You could create a site where only certain people are allowed to make international calls with an International Number Plan. You also may want to suggest a passcode feature to allow international dialing in the Product Ideas Lab.
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Jason Kleitz
Online Community Manager/Moderator
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