Contacts and calendar items are backed up with both types of Exchange backups (Information Store and Mailbox Level.)
Mailbox Level backups offer a faster way to restore a small number of items since you can browse to the individual mailbox and simply restore the affected items directly into Exchange or to a (.pst) file.
With a full Information Store backup, you can also restore contacts and calendar items, however, it is necessary to put the entire restored database into a recovery storage group and use Exmerge or a similar tool to get data into the appropriate active storage group.