IMPORTANT NOTE: You must buy at least 5 CALS. New orders must also purchase a server license The new capabilities of Microsoft Exchange Server 2007 deliver the advanced protection your company demands the anywhere access your people want and the operational efficiency you need. There is a reason Exchange Server 2007 is the industry's leading server for e-mail calendaring and unified messaging. The Exchange Server Standard CAL provides access to e-mail shared calendaring and Outlook Web Access. In addition you will get advancements that reduce the cost and complexity of the messaging system by giving IT Administrators the messaging protection their company demands the anywhere access their end users want and the reliability they need.Microsoft Open Licensing allows the ability to purchase under the same authorization number for two years. Open Business offers volume pricing with only a five minimum license requirement.