With a BlackBerry, you don't have to specifically make a request to check for email. By itself, the device constantly polls, looking for new mail. It sends out poll requests over an existing wireless network, such as a cell phone network. You can use a BlackBerry to check your personal mail or your corporate mail. This illustration shows how you use it to check your corporate mail.
Blackberries can do more than request email. They also can get corporate information sent to them as well. In this instance, the BlackBerry Enterprise Server routes the request to another kind of corporate server, such as a Customer Relationship Management (CRM) system, instead of an email server.