SMS

The 160-character limit that defined a generation of communication was not a design choice—it was discovered empirically by a German engineer typing random sentences at his home in Bonn. In 1984, Friedhelm Hillebrand sat at his typewriter, wrote message after message, and counted characters. Nearly every meaningful communication fit within 160 characters. When the GSM technical committee challenged his methodology, he analyzed thousands of postcards and telex messages, reaching the same conclusion. The constraint became the standard.

SMS emerged from a brilliant piece of engineering opportunism: using the signaling channels of the GSM cellular network during idle periods. These channels, designed to coordinate calls between phones and cell towers, sat empty most of the time. The insight was that short text bursts could hitchhike on this existing infrastructure at essentially zero marginal cost. But the 140-byte payload limit of signaling channels, combined with 7-bit GSM character encoding, yielded exactly 160 characters—Hillebrand's empirical finding matched the technical constraint perfectly.

The Franco-German GSM cooperation developed the SMS concept in 1984, but the first message would not be sent until December 3, 1992. On that date, Neil Papworth, a test engineer at Sema Group in the UK, typed "Merry Christmas" on a computer and sent it to Richard Jarvis's Orbitel 901 phone via the Vodafone network. Mobile phones lacked keyboards—the message had to originate from a PC. This asymmetry would persist until Nokia integrated SMS composition into handsets in 1993.

The convergent emergence across Europe reveals the inevitability. Germany developed the specification, France contributed to standardization, the UK hosted the first transmission, and Finland's Radiolinja launched the first commercial person-to-person service in 1994. Sweden's TeliaSonera followed. The technology emerged simultaneously wherever GSM networks were being deployed because SMS was not a separate invention—it was an exploitation of existing network architecture.

Initial adoption was glacially slow: customers sent an average of 0.4 messages per month in 1995. The technology seemed like an afterthought. But path dependence was accumulating invisibly. Every GSM phone shipped with SMS capability. Every network deployed the infrastructure. By the time prepaid mobile plans made texting cheaper than calling for teenagers in the late 1990s, the installed base was enormous.

The 160-character constraint would shape communication far beyond mobile phones. When Twitter launched in 2006, its 140-character limit paid direct homage to SMS—leaving 20 characters for usernames. The discipline of brevity that Hillebrand discovered at his typewriter in 1984 became the foundation for microblogging, two-factor authentication, and mobile payments across the developing world. A technical limitation became a cultural form.