Destination Code Control (DCC) allows you to restrict outbound calls to a specific called number or a range of numbers. In the Precedence Routing Digit Analysis Table screen, the Destination Code Control and Percentage IPBO Blocked fields are used for destination code control.

For example, when you set the Destination Code Control to y and Percentage IPBO Blocked to 50%, Communication Manager blocks 50% of the outbound call from the total outbound IP call budget (IPBo) when a certain number or a range of numbers is called.

If the total outbound IP call count (IPCo) reaches 50% that is equal to IPBo, and a user makes a routine call, then the routine call is denied. However, if the user makes a priority or an immediate call, then the lower precedence call in the trunk is preempted to connect the new call. DCC follows precedence rule for group or route settings on the Preempt Method field.