Enterprise Voice provides a simple mechanism for assigning or restricting calling privileges for internal users. You can define a single voice policy for all users in your organization or multiple voice policies to define call privileges for different individuals and groups. You can define as many policies as you like. You can even define a policy but not assign it to anyone.
An Enterprise Voice policy is a named set of Enterprise Voice phone usages. Phone usages are simply labels that you create to identify particular types of calls; for example, Local calls only or Local + Long Distance. You can create as many phone usages as you like. When you create an Enterprise Voice policy, you add the phone usages you want to include in the policy and give the collection a name.
You also associate phone usages with Enterprise Voice outbound call routes that you have defined. By assigning phone usage records to both user policies and outbound call routes, you indicate which users are allowed to make calls that use particular routes. When a user places a call, Office Communications Server matches the caller with the route. If the phone usage record for the route also appears in the Enterprise Voice policy assigned to the caller, the call is allowed to go through. If the caller’s policy does not include a phone usage record that matches one of those assigned to the route, the server refuses the call.