SMS is a form of text electronic communications, which allows the sending of short messages between mobile and land-based phones. The use of standardized communications protocols allows this form of communication to take place seamlessly and has made SMS, or short messaging service, the most used data application in the world.
SMS was first conceptualized in 1982, and first developed in 1984. Because SMS was optimized to work over then-current telephony systems, it was widely used in early networks and mobile communications processes. Those initial message set a limit of 160 characters (or 140 bytes), allowing them to be sent over the existing network structure. This also meant that mobile stations could be upgraded to accept SMS communications with a simple software update.
The first SMS message was sent over the Vodaphone network, and was a simple message; “Merry Christmas.”
From these humble beginnings, SMS use has become a multibillion dollar commercial enterprise, earning over $100 billion annually. The global average cost of sending an SMS message is eleven cents per message, with an average of four cents being paid towards interconnect fees when the message must cross networks.
In addition to standard charges for simply sending an SMS message, the service can be used for the transfer of premium services. An example of this type of service would include the delivery of premium ringtones.
When a user sends a message by SMS, it is received by a short message service center or SMSC. The SMSC then stores the message and attempts to forward it to the message recipients. If the message center is unable to successfully connect with the recipient, it then tries to resent the message at regular intervals.
Although the SMSC makes a noble attempt to send all messages, messages occasionally disappear or never reach their recipient. This is normally not an issue, as SMS messaging has approximately a 95% success rate. In the case of a network that is overloaded, SMS is given a lower priority than other types of communication, especially that of voice. In these circumstances, such as during a major emergency in a large metropolitan area, the rate of lost or undelivered or delayed SMS messages can increase dramatically. Because of this unreliability, SMS has been criticized as a source of delivery of important and critical emergency service messages.
Most messages sent from businesses to mobile customers make use of an SMS Gateway, which facilitates the delivery of the message from the originating business to the networks used by the phone. This is often used for important messages or such communication as TV voting.
The police have also learned how to make use of SMS technology. Many law enforcement agencies are capable of sending a “silent SMS” which will “ping” the specified user’s phone. Such silent SMS messages create no visible or audible sign of their presence, but still create data on the mobile carrier’s network, thus allowing the law enforcement agency to get an idea of the location of the user of the mobile phone, or to use information from multiple silent SMS messages to get an idea of a specific person’s routine movements throughout an area.
Though overall a very safe way to communicate, like many things involving the internet, SMS does have its own vulnerabilities. These vulnerabilities include a possible lack of effective encryption that allows malicious entities to intercept and hack the message, gaining access to the information within. By necessity, the networks upon which these messages travel must remain open, and that alone can lead to a vulnerability that can be exploited by those seeking to steal messages.