thumb|An SMS message received on a [[Siemens SL55]]
Short Message Service (SMS) is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile phones exchange short text messages, typically transmitted over cellular networks.
Developed as part of the GSM standards, and based on the SS7 signalling protocol, SMS rolled out on digital cellular networks starting in 1993 and was originally intended for customers to receive alerts from their carrier/operator. The service allows users to send and receive text messages of up to 160 characters, originally to and from GSM phones and later also CDMA and Digital AMPS; it has since been defined and supported on newer networks, including present-day 5G ones. Using SMS gateways, messages can be transmitted over the Internet through an SMSC, allowing communication to computers, fixed landlines, and satellite. MMS was later introduced as an upgrade to SMS with "picture messaging" capabilities.
In addition to recreational texting between people, SMS is also used for mobile marketing (a type of direct marketing), two-factor authentication logging-in, televoting, mobile banking (see SMS banking), and for other commercial content. The SMS standard has been hugely popular worldwide as a method of text communication: by the end of 2010, it was the most widely used data application with an estimated 3.5 billion active users, or about 80% of all mobile phone subscribers. More recently, SMS has become increasingly challenged by newer proprietary instant messaging services; RCS has been designated as the potential open standard successor to SMS. The first SMS message was sent on 3 December 1992, when Neil Papworth, a test engineer for Sema Group, sent "Merry Christmas" to the Orbitel 901 phone of colleague Richard Jarvis.
Initial concept
Adding text messaging functionality to mobile devices began in the early 1980s. The first action plan of the CEPT Group GSM was approved in December 1982, requesting that "The services and facilities offered in the public switched telephone networks and public data networks ... should be available in the mobile system." This plan included the exchange of text messages either directly between mobile stations, or transmitted via message handling systems in use at that time.
The SMS concept was developed in the Franco-German GSM cooperation in 1984 by Friedhelm Hillebrand and Bernard Ghillebaert. The GSM is optimized for telephony, since this was identified as its main application. The key idea for SMS was to use this telephone-optimized system, and to transport messages on the signalling paths needed to control the telephone traffic during periods when no signalling traffic existed. In this way, unused resources in the system could be used to transport messages at minimal cost. However, it was necessary to limit the length of the messages to 128 bytes (later improved to 160 seven-bit characters) so that the messages could fit into the existing signalling formats. Based on his personal observations and on analysis of the typical lengths of postcard and Telex messages, Hillebrand argued that 160 characters was sufficient for most brief communications.
SMS could be implemented in every mobile station by updating its software. Hence, a large base of SMS-capable terminals and networks existed when people began to use SMS. A new network element required was a specialized short message service centre, and enhancements were required to the radio capacity and network transport infrastructure to accommodate growing SMS traffic.
Early development
The technical development of SMS was a multinational collaboration supporting the framework of standards bodies. Through these organizations the technology was made freely available to the whole world.
The first proposal which initiated the development of SMS was made by a contribution of Germany and France in the GSM group meeting in February 1985 in Oslo. This proposal was further elaborated in GSM subgroup WP1 Services (Chairman Martine Alvernhe, France Telecom) based on a contribution from Germany. There were also initial discussions in the subgroup WP3 network aspects chaired by Jan Audestad (Telenor). The result was approved by the main GSM group in a June 1985 document which was distributed to industry. The input documents on SMS had been prepared by Friedhelm Hillebrand of Deutsche Telekom, with contributions from Bernard Ghillebaert of France Télécom. The definition that Friedhelm Hillebrand and Bernard Ghillebaert brought into GSM called for the provision of a message transmission service of alphanumeric messages to mobile users "with acknowledgement capabilities". The last three words transformed SMS into something much more useful than the electronic paging services used at the time that some in GSM might have had in mind.
SMS was considered in the main GSM group as a possible service for the new digital cellular system. In GSM document "Services and Facilities to be provided in the GSM System," Here a rudimentary description of the three services was given:
- Short message mobile-terminated (SMS-MT)/ Point-to-Point: the ability of a network to transmit a Short Message to a mobile phone. The message can be sent by phone or by a software application.
- Short message mobile-originated (SMS-MO)/ Point-to-Point: the ability of a network to transmit a Short Message sent by a mobile phone. The message can be sent to a phone or to a software application.
- Short message cell broadcast. mentions for the first time the Technical Specification 03.40 "Technical Realisation of the Short Message Service". Responsible editor was Finn Trosby. The first and very rudimentary draft of the technical specification was completed in November 1987. However, drafts useful for the manufacturers followed at a later stage in the period. A comprehensive description of the work in this period is given in.
Early implementations
The first SMS message was sent over the Vodafone GSM network in the United Kingdom on 3 December 1992, from Neil Papworth of Sema Group (now Mavenir Systems) using a personal computer to Richard Jarvis of Vodafone using an Orbitel 901 handset. The text of the message was "Merry Christmas."
The first commercial deployment of a short message service center (SMSC) was by Aldiscon part of Logica (now part of CGI) with Telia (now TeliaSonera) in Sweden in 1993, followed by Fleet Call (now Nextel) in the US, Telenor in Norway and BT Cellnet (now O2 UK).
The first commercially sold SMS service was offered to consumers, as a person-to-person text messaging service by Radiolinja (now part of Elisa) in Finland in 1993. Most early GSM mobile phone handsets did not support the ability to send SMS text messages, and Nokia was the only handset manufacturer whose total GSM phone line in 1993 supported user-sending of SMS text messages. According to Matti Makkonen, an engineer at Nokia at the time, the Nokia 2010,<!--Not 2110--> which was released in January 1994, was the first mobile phone to support composing SMSes easily.
Growth and adoption
Initial growth was slow, with customers in 1995 sending on average only 0.4 messages per GSM customer per month. Initially, networks in the UK only allowed customers to send messages to other users on the same network, limiting the usefulness of the service. This restriction was lifted in 1999. SMS had become a social phenomenon in Finland among teens and youngsters by 1999. SMS traffic across Europe reached 4 billion messages as of January 2000.
SMS became extremely popular in the Philippines by 2001 and the country was dubbed the "texting capital of the world", partly helped by large numbers of free text messages offered by the mobile operators in monthly subscriptions. SMS adoption was limited to parts of Europe and Asia during these earlier years, with U.S. adoption being low partly due to incompatible networks and cheap voice calls relative to other countries.
This is also backed by the fact that as of 2003, American internet users were spending on average five times more time online than Europeans, and many poorer countries in Europe and other regions around the world had significantly lower rates of internet access compared to the United States at the time (see digital divide), hence making SMS more accessible.
Contemporary usage
thumb|SMS messages sent monthly in the U.S. from 2001 to 2008 (in billions)