Sms is an acronym for short message service, it is used to send text messages to mobile phones. The text message has a limit of number of characters that can fit in one message. Initially the limit was 160 characters, but this has changed with technology advancement.
The short message service uses special communication protocols to allow mobile phone (devices) to exchange text messages.
Originally sms was designed for to be used by GSM (Global system for mobile communication) however, in recent times, sms has been adopted by web based applications to send information automatically or depending on certain conditions.
The destination (Phone) does not need to be switched on. If the recipient phone is off, the message will be stored by the server and delivered once the device is switched on.
Recently, sms has been adopted for disseminate information such as weather updated, stocks, sports, news, and product information among others.