SMS is a text (short) message service, uses standardized communication protocols to enable mobile devices to exchange short text messages. SMS, as used on modern devices, originated from Radio Telegraphy in radio memo pagers that were standardized phone protocols. These were defined in 1985, as part of the Global System for Mobile Communications (GSM) series of standards.
The first SMS message was sent in 1992. The maximum length of an individual message goes up to 160 alpha-numeric 7 bits characters (but in case of 5 bits mode, it can supports 224 characters). A SMS message is stored temporarily in the SMS centre if the recipient mobile phone is unavailable.
