Before you can use UM and OVA, you need to configure your UM server role.
Before you can use UM, you need to install an Exchange server that includes the UM server role. You can add the UM role to every server role except for the Edge Transport server role.
Depending on the size of your environment, you can decide whether you want to deploy the UM role on a server that already hosts a role, or use a dedicated server to host the UM server role. You can find more details how to deploy the UM server role in Chapter 15.
You need to create a UM dial plan to configure the number of extensions the UM server will be accept. Each UM dial plan requires a specifically set URI type ...