In Exchange 2010 there are multiple default address lists available, like All Users, All Groups, All Contacts, and there’s an All Rooms Address list for all Room Resource Mailboxes:

When opening the All Rooms address list, you can see it uses a custom filter to get all the room mailboxes from the Exchange organization:

You can also create Equipment Resource Mailboxes, for example for beamers. But when you want to do this using the Management Console, there’s only the option to create an address list for Resource Mailboxes in general, which includes both the Room Mailboxes as well as the Equipment Mailboxes.

If you want to create an address list only for Equipment Mailboxes, you have to create an address list from the Exchange Management Shell and use a custom filter, like:

-RecipientFilter {(Alias –ne $null –and (RecipientDisplayType –eq ‘EquipmentMailbox’ or RecipientDisplayType –eq ‘SyncedEquipmentMailbox’))}

After creating the address list is needs to be ‘applied’ as well, which can be done using the Update-AddressList cmdlet:

Update-AddressList -identity “All Equipment”

Now when you open Outlook and check the address book, you’ll see the “All Equipment” address list with the beamer that are (previously) created.

And when you select the “All Rooms”, you’ll only the available Room Mailboxes: