What is SMS?

Short Message Service (SMS) is the ability to send and receive text messages to and from mobile telephones. The initial standards were first discussed in the early 1980s but the world’s first commercial SMS service by Radiolinja Oy in Finland was not introduced until 1992. SMS was created as part of the GSM Phase 1 standard.

Each short message is up to 160 characters* in length. The 160 characters can comprise of words, numbers, or punctuation symbols. Short messages can also be non-text based such as binary.

The Short Message Service is a store and forward service, this means that messages are not sent directly to the recipient but via a network SMS Centre. This enables messages to be delivered to the recipient if their phone is not switched on or if they are out of coverage at the time the message was sent - so called asynchronous messaging just like email. Confirmation of message delivery is another feature and means the sender can receive a return message notifying them whether the short message has been delivered or not. In some circumstances multiple short messages can be concatenated (stringing several short messages together.

* The actual limit of size of SMS is 160 characters if Latin alphabets are used. If non-Latin alphabets like Chinese or Arabic are used, the limit is 70 characters.