How SMS Works

SMS has several advantages. It is more discreet than aphoneconversation, making it the ideal form for communicating when you don't want to be overheard. It is often less time-consuming to send a text message than to make a phone call or send an e-mail. SMS doesn't require you to be at your computer likee-mailandinstant messaging(IM) do -- although some phones are equipped for mobile e-mail and IM services. SMS is also a convenient way for deaf andhearing-impaired people to communicate.

SMS is a store-and-forward service, meaning that when you send a text message to a friend, the message does not go directly to your friend's cell phone. The advantage of this method is that your friend's cell phone doesn't have to be active or in range for you to send a message. The message is stored in the SMSC (for days if necessary) until your friend turns his cell phone on or moves into range, at which point the message is delivered. The message will remain stored on your friend'sSIM carduntil he deletes it.

In addition to person-to-person messages, SMS can be used to send a message to a large number of people at a time, either from a list of contacts or to all the users within a particular area. This service is calledbroadcastingand is used by companies to contact groups of employees or by online services to distribute news and other information to subscribers.

In a 2004 University of Plymouth study on the psychology of SMS users, researchers found that mobile phone users were primarily either "texters" or "talkers." Compared to the talkers, the texters sent nearly double the number of SMS messages and made less than half as many voice calls per month. The texters preferred SMS to voice calls for its convenience as well as for the ability to review a message before sending it.

Companies have come up with many uses for the service beyond just your typical person-to-person message. Because SMS doesn't overload the network as much as phone calls, it is frequently used byTVshows to let viewers vote on a poll topic or for a contestant. As a promotional tool, wireless carriers put upgiant screensat concerts and other large-scale events to display text messages from people in the audience.

You can use text messaging subscription services to get medication reminders sent to your phone, along with weather alerts, news headlines or even novels broken into 160-character "chapters." Internetsearch enginessuch as Yahoo! and Google have short messaging services that enable users to get information such as driving directions, movie showtimes or local business listings just by texting a query to the search engine's phone number. Social networking services such as Dodgeball use SMS to alert people who live in big cities when their friends or crushes are nearby. The possibilities for integrating SMS into your lifestyle seem endless.

Next, we'll discuss the disadvantages of SMS and look at some alternative communication technologies.

Despite their popularity, short messaging services have received some criticism. Here are a few of the disadvantages of SMS:

Alternatives to SMS

Alternative messaging services allow for more elaborate types of messages. WithEMS(Enhanced Messaging Service), you can send formatted text, sound effects, small pictures and icons.MMS(Multimedia Messaging Service) allows you to send animations, audio and video files in addition to text. If yourmobile phoneis EMS- or MMS-enabled, you can use these standards just as you would SMS. However, the cost per message will be higher.

Another alternative to using SMS is using aninstant messagingprogram, such as AOL IM, on your cell phone. This can be in the form of software that's pre-installed on your phone, or you can useWAP(Wireless Application Protocol) to access the Internet and sign into your IM account. WAP is a protocol that gives you small, simplified versions of web pages that are easily navigable on your mobile phone or PDA (check outHow WAP Worksfor more information). You can use it to send instant messages or actuale-mailsfrom your phone.

A common complaint about SMS is its inefficient delivery structure -- when the message center is backed up, messages take longer to reach their destination. To make message delivery faster, networks are using more new next-generation technologies such asGPRS(General Packet Radio Service).

To learn more about SMS and other forms of mobile communication, check out the links on the following page.