If you mean you want a PIN so they can call, that's not possible in either system.
ie phone is locked, you enter username and/or pin and then you can make calls.
You can use FAC on CME or FAC/CMC on CUCM, but both of those are only for making external calls and ask for a valid code so it proceeds. If you're interested in either, review the online documentation for CME/CUCM or search CSC as there are plenty of threads on the subject.
If you want the 1st scenario you would need a 3rd party solution.
HTH
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www.cisco.com/go/pdihelpdesk
HTH
java
if this helps, please rate