SMS stands for Short Message Service. SMS are being exchanged on mobile devices. Each SMS message is normally limited to 160 characters with spaces. The first test SMS was sent in 1992.
The service allows users to send and receive messages of up to 160 characters (when entirely alpha-numeric) to and from GSM mobiles. Though most SMSs are sent from one phone to another, the service has expanded to include other mobile technologies, such as CDMA networks and Digital AMPS. Mobile direct marketing efficiently uses SMS. It provides a maximum of 16 digits if the origin is numeric (e. g. a phone number), or a maximum of 11 alphabetic characters and digits when the origin is alphanumeric (e. g. a company name).