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What is SMS and how does texting work?

Last updated October 2023

Since the very first Short Messaging Service (SMS) message was sent in 1992, the practice of sending messages between mobile phones has well and truly taken off. Today, around 18.7 billion text messages are sent worldwide each day. 

SMS has become one of the most popular forms of communication. And for great reason. It’s an incredibly quick and easy way to get in touch with other people. Plus, it’s super cost-effective for businesses, too. 

Yet, while most people happily send text messages every day, many don’t know much about how this communication system works – beyond the fact that a standard message has 160 characters or less (and, let’s face it, even this is news to some). Let’s break down SMS and explore how it all works.

DID YOU KNOW: SMS messages use communication protocols that were standardized in 1985 by the Global System for Mobile Communications (GSM). In the GSM system, an SMS message is limited to 160 characters. Learn more about GSM character types and message lengths.

Messaging types: Unpacking all the text-based acronyms.

“I’ll send you a text.” It’s a common call. But, technically, the term ‘text message’ can mean a few different things. See, texting is an umbrella term for all kinds of services and products that allow you to send and receive text-based messages.

Before we dive into how SMS works, let’s look at all the different types of text messages. They include:

  • SMS, which stands for Short Messaging Service. This consists of alphabetic and numerical characters. At 160 characters or less, it’s pretty clear why this type of text gets called ‘short’.
  • MMS, which stands for Multimedia Messaging Service. You’ve got more room to move with this. You can include up to 5,000 characters in the main message, plus a subject line of up to 20 characters and images (for example, a JPEG, PNG or moving GIF). Learn more about MMS.
  • Mobile Landing Pages (MLPs). Technically, an MLP isn’t a text message. But these mobile-friendly, feature-rich pages are linked to from standard SMS as a way to boost engagement with customers. Here are 10 great use cases for Mobile Landing Pages.
  • Over-the-top (OTT) application messaging. Applications like Whatsapp, iMessage and Facebook Messenger use a slightly different way to send text messages. Whereas SMS, MMS and MLP use a telecommunications network to transmit messages, OTT messaging requires an internet or WIFI connection.

How does SMS work?

The way SMS works can depend on who is sending the message. If you’re sending a message from your phone to a friend’s phone, you’ll just use your mobile phone network. Businesses, on the other hand, use a gateway like MessageMedia to send huge volumes of messages out to customers. Let’s take a look at both.

Sending SMS between friends.

Graphic showing P2P text messaging works

Here’s what happens (in very simple terms) when you type out a message to a mate on your phone. When you hit ‘send’, your mobile phone carrier uses the GSM system to convert the message and the recipient’s mobile phone number into data sent to the nearest mobile phone tower.

From there, it’s routed to the tower closest to the recipient, where the data lands on your friend’s phone, unscrambled as your message.

Sending SMS from your business.

Graphic showing how A2P business text messaging works

While the carrier network works well for single messages, it’s not as effective for businesses that want to send out bulk SMS messages to all their customers. Enter the gateway.

Gateway technology solves the challenge of sending messages out to thousands of customers in one go, quickly and reliably. A gateway is an online platform or engine that can rapidly intake and direct huge volumes of SMS in a short amount of time – making it ideal for businesses that send bulk SMS

For example, Sinch MessageMedia’s gateway can process +10,000 events per second and deliver 95% of messages within 2 seconds. And, with Sinch MessageMedia, you’ve got options for how you access the gateway to send your bulk SMS messages:

  • Our self-service web portal. Send and receive SMS directly from the web portal.
  • Email to SMS. If your team prefers the familiarity of email, you can easily send SMS from your email inbox.
  • Integrated with your preferred platform. Through our integrations marketplace, you can easily connect MessageMedia with your preferred sales, marketing or other business tools to send text messages from them.

How our SMS gateway works.

Our SMS gateway routes messages directly through a provider (which could be a telecommunications network or carrier). It uses rules to quickly decide which provider offers the best, fastest and most reliable route to deliver the message. 

A number of factors come into play here, including the message content, the recipient and sender’s carrier, the type of message (for example, SMS or MMS), and so much more. The most important consideration? Which pathway will take the least number of hops for your message to get to its recipient.

DID YOU KNOW: Our gateway automatically minimises the number of ‘hops’ your message needs to take. A ‘hop’ is when a data packet passes to another network segment (for example, going from the Telstra network in Australia, to the AT&T network in the US).

With the best route identified, the message then passes through the gateway and is delivered to the recipient. With everything happening automatically, it’s a highly scalable system that enables businesses to ‘blast’ out mass messages almost instantaneously.

Ready to take our SMS platform for a spin?


FAQs about SMS.

The meaning of SMS in texting is Short Message Service (SMS). This is a protocol for mobile devices that allows quick and simple text-based communication.

SMS is limited in that it cannot use images, and the length of a standard message is limited to 160 characters.

Over-the-top (OTT) is a form of messaging that uses the Internet to exchange messages between devices.

For example, WhatsApp, Instagram DMs, Meta Messenger, and Google Business Messages are all examples of OTT messaging.

These are in contrast to technologies like SMS messaging which send messages through mobile data carriers like Verizon or AT&T.

Text message protocols like SMS and MMS are a form of chat, but they are not the only way that people can chat with each other through mobile devices.

For example, OTT messaging through apps like WhatsApp, Meta Messenger or Instagram can accomplish the same goals as SMS. Instead of using mobile data carriers, OTT messaging can be achieved entirely through the internet.