In the fast moving world of technology, there are perhaps few things that have proved as resistant to change as the simple SMS text message.
While a dizzying number of options exist today to interconnect people, the text message remains a 160 character deliverer of news, gossip, laughs, alerts, and all manner of other information. It connects more people than Facebook and Twitter, has brought down governments, and in so much of the world still holds the ability to change lives.
Dec. 3 is the 20th anniversary of the sending of the first SMS text message.
Today, upwards of 7 trillion text messages are sent every year -- that's more than 200,000 per second -- but the technology had humble beginnings.
Its origins can be traced back to a Danish pizzeria in 1984. Matti Makkonen, a Finnish engineer, was in Copenhagen for a mobile telecom conference and began discussing with two colleagues the idea of a messaging system on the GSM digital cellular system. At the time GSM was a Nordic technology, becoming a European standard later.
Eight years later, SMS had become a standard and Neil Papworth, an engineer working for Sema Group in the U.K., was one member of a team developing SMS service center software for Vodafone.
The development work had been going on for most of the year and on Dec. 3, 1992, Papworth made the 30 minute journey from Sema's offices in Reading to Vodafone's headquarters in Newbury. Both are in Berkshire, just west of London.
Testing had been taking place for weeks. Just as today, Vodafone had a stringent series of checks to be carried out before Sema's SMS system could be interconnected with its network.
The approval was finally given and the systems interconnected, then Papworth, sitting in front of a personal computer, tapped out the greeting "Merry Christmas" and sent it via SMS to Vodafone Director Richard Jarvis.
The text-messaging era was born.
Jarvis received the message on an Orbitel 901 "transportable" cellphone. The device was mammoth by today's standards, weighing 2.1 kilograms -- equivalent to just over 17 iPhone 5 handsets.
"People always ask me if it was a monumental occasion," said Papworth in an interview. "For me, I was working for Sema, Vodafone paid us to write the software and we got the job done."
Text messaging's main use at first was to inform subscribers of waiting voicemails, and it was offered at no cost. In itself, that was an innovation because users would otherwise periodically call their voicemail box to see if it contained any new messages.
Perhaps it's no surprise then that in late 1995, three years after Papworth's first text message, users were only sending an average of one text every two and a half months.
It took SMS several years to take off -- and for some of that time, Papworth didn't have a cellphone.
"It took me a long time to get a cellphone. But I remember, I went to the Ideal Home Exhibition in London and Vodafone had an offer so I finally bought one," he said. "Back then, I didn't think I needed one. I only got a few calls a day."
The introduction of prepaid cellular service and innovations like T9 predictive text input helped the market grow and in 2000 the industry counted 17 billion text messages, according to data from Ericsson. That number grew by around 20 times over just the next two years.
It's estimated that there are around 6 billion cellphone subscribers today and almost all of them have access to SMS.
"The market is almost saturated, but it continues to grow with the growth of the planet," said JF Sullivan, chief marketing officer at Acision. The U.K. based company accounts for about a third of the SMS messaging system market and customers include the likes of Vodafone, Telefonica, Telia Sonera and Sprint.
"Everyone continues to use SMS and it doesn't look like it's dropping off anytime in the future," he said.
Part of the success of SMS -- perhaps its key to success -- is its universal availability.
"You can still get to everyone," said Sullivan. "All of those people holding a handset can be reached."
Looking back on the last 20 years since he sent that first message, Papworth says he's not surprised at how successful SMS has become.
"At the time, I never thought it would be so big," he said. "Now I see what it has become, I'm not surprised because it's so easy. It's on all phones. Not everyone has a smartphone and GSM is still rolling out in some countries. In those countries, not all customers will have a smartphone, but at least everyone will have a basic phone."
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is firstname.lastname@example.org