Overview

E-mail s primary use, of course, is to enable humans to send and receive messages over a network. But many embedded systems can make good use of e-mail as well. E-mail can be a convenient way for an embedded system to exchange information with humans or even communicate with other embedded systems with no human intervention at all.

For example, a security system can be programmed to send a message when an alarm condition occurs. Or a data logger might send a message once a day with the logger s readings for the previous 24 hours. In the other direction, an embedded system might receive e-mail containing new configuration settings or other commands, requests, or data.

E-mail has a couple of advantages over other methods of communication. Recipients can retrieve and read their messages whenever they want. And if the information isn t time-critical, the sender might find it easier or more efficient to place the information in an e-mail and send it off when convenient, rather than having to respond in real time to requests for the information. Another advantage is that an account with e-mail access alone can be less expensive than an account that supports hosting a Web server or performing other TCP/IP communications.

A down side to e-mail is that recipients might not receive information as quickly as needed if they don t check their e-mail regularly or if an e-mail server at either end gets backed up and delays delivery.

This chapter begins with examples that show how...