Exchange ActiveSync® is a communication protocol that enables mobile, "over-the-air" access to e-mail messages, schedules, contacts, tasks, and other Exchange Server mailbox data. When using Microsoft Windows Mobile–based phones, or Exchange ActiveSync–enabled mobile phones that are available through Microsoft partners, it's easy to gain mobile access to Exchange Server for e-mail messages, schedules, contact information, and tasks. You can get your work done nearly anytime, anywhere, with Exchange ActiveSync–compatible devices.