The MWI addresses are used primarily for message waiting notifications. It is also used to support multiple extensions in a guest room, so that name, DND, and restriction class of service changes can be sent to the PBX for all extensions associated with a guest room.
Most PBXLinks will use all the MWI addresses as a source for name changes as well. If name changes are supported by the PBXLink, the DV2000 will attempt to change the name for each MWI address in the list. This ensures rooms with multiple extensions are properly configured.
While the MWI address is typically set to an extension number, on SIP-enabled systems you can also set it to a full SIP address if you need to. For example, 7101@192.168.100.60 would be a valid MWI address for extension 7101. The IP address (192.168.100.60) can be for either the physical phone, the gateway, or even another PBX. It is also possible to use a domain name (e.g., 7101@yourdomain.net).