There is a paper on CCO .
TCP and UDP Ports Used by Cisco CallManager
Who list port used by CallManager and since : "Cisco Unity voice ports are registered via the TAPI service provider (TSP) using the Skinny protocol (TCP port 2000)."
Other ports information can be find in : Cisco Unity QoS paper that describes any additional ports used (primarily between Microsoft Exchange and Cisco Unity)
And note that UNITY may interacted with an external MS AD .
Martin