s typically away from their desks at any one time, it is important for them to keep in touch with the office by extending the use of corporate e-mail systems beyond an employee's office PC. Corpo- rate e-mail systems run on Local Area Networks (LAN) and include Microsoft Mail, Outlook, Outlook Express, Microsoft Exchange, Lotus Notes, and Lotus cc:Mail. Because GPRS-capable devices will be more widespread in corporations than among the general mobile phone user community, more corporate Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. GPRS Introduction Chapter 2 e-mail applications are likely to use GPRS than Internet e-mail applica- tions whose target market is more general. Internet E-mail Internet e-mail services come in the form of a gateway service where the messages are not stored, or mailbox services in which messages are stored. In the case of gateway services, the wireless e-mail platform translates the message from SMTP, the Internet e-mail protocol, into SMS and sends it to the SMS Center. In the case of mailbox e-mail services, the e-mails are actu- ally stored and the user receives a notification on his or her mobile phone and can then retrieve the full e-mail by dialing in to collect it, forward it, and so on. Upon receiving a new e-mail, most Internet e-mail users are not cur- rently notified of this fact on their mobile phone. When they are out of the office, they have to dial in speculatively and periodically to check their mail- box contents. However, by linking Internet e-mail with an alert mechanism such as SMS or GPRS, users can be notified when a new e-mail is received. Vehicle Positioning This application integrates satellite-positioning systems that tell people where they are with nonvoice mobile services that enable people to tell oth- ers where they are. The Global Positioning System (GPS) is a free-to-use global net