I have a great doubt, I need to monitor when a phone goes from registered to unregistered and when this happens an alarm must be created using Prime Collaboration Assurance.
I´m new in PCA so I´d like to know if this is possible
PCA doesn't do this for each phone individually as that would be chaotic and simply unmanageable in a network with large number of endpoints. Instead you can setup a PhoneUnregThresholdExceeded per device pool and have it alert you when it hits those limits.