How to disable captain PIN for a data call using Iridium Captain SIM?

Dial 698698 to enter the Crew Calling platform.  

Enter your PIN.  Then you are presented with 4 choices.  

Enter "3" to activate the captain's PIN for voice calls only.  

After you do this, you will always be prompted for a PIN when making voice calls, however you will never have to enter a PIN for data calls.