WHAT IS AN SMS?

SMS stands for short message service. SMS is also often referred to as texting, sending text messages or text messaging. The service allows for short text messages to be sent from one cell phone to another cell phone or from the Web to another cell phone. 
The original specifications for SMS were developed in 1985, though real implementation and popularity took nearly a decade to achieve.

The most common mobile keypad alphabet layout

Including spaces, text messages traditionally can’t exceed 160 characters. SMS messages often use T9 predictive technology. T9 makes text messaging faster and more efficient on non-QWERTY cell phones without full keyboards.

SMS text messaging is the most widely used data application in the world, with 2.4 billion active users, or 74% of all mobile phone subscribers