Insights & Resources10 min read

What is SMS? How Short Message Service Works

As one of the most commonly used messaging technologies in the world, learn what SMS is and how it can help your business.

Risa Takenaka
Sending SMS text message
SMS is the most used text messaging service in the world. Businesses use SMS for marketing, service fulfillment, and customer service, among other things.
Most people get text messages every day, so you’re probably familiar with SMS from an end user perspective. But receiving an SMS message doesn’t reveal exactly how the technology works.
So just what is SMS? How does it work? And why might you choose SMS over another messaging service?

What is SMS?

SMS, which stands for Short Message Service, is the text messaging service on most mobile phones and other mobile devices. SMS is based on standardized communication protocols to send text messages from device to device. The standardized nature of SMS is the primary reason that it’s the most ubiquitous text messaging service.
SMS is ideal for sending short, text-only messages. We’ll get into the pros and cons shortly. But SMS is a cost efficient and widely available media for sending text messages.
However, SMS is not the only text messaging service.
Apple devices are capable of sending text messages via iMessage, which is a separate service. And Android has developed RCS, which is similar to iMessage, but for Android phones. Then there are other messaging apps—like Facebook messenger—that offer a similar experience to SMS, though they’re not as widely used.
These app-based messaging services are OTT (Over the Top) messaging services. They’re viable alternatives to SMS, though they’re not as widely used as SMS.
But MMS (Multimedia Messaging Service) is the most common alternative to SMS. MMS uses standardized protocols, which makes it compatible with more devices than iMessage or RCS, which is why it gets used more than those proprietary messaging services.
Here’s what separates these other messaging services from SMS.

Difference between SMS and MMS

MMS is similar to SMS in terms of device compatibility. However, MMS (Multimedia Messaging Service) is capable of sending multimedia content—images, videos, and audio—in addition to transmitting text.
This may lead you to wonder why one would use SMS over MMS, if MMS is more capable and compatible with the same devices.
The answer is that SMS is still more cost and data efficient if you’re only sending text. In most cases, sending an MMS message is more expensive than sending an SMS message, even if the message contains no multimedia content.
Additionally, most carriers have lower send volume limits for MMS messages. This is because MMS messages are almost always larger than SMS messages, so most carriers aren’t able to send as many MMS messages as fast as you can send SMS messages.
Ultimately, MMS is indeed more capable than SMS. It’s just not quite as efficient for sending text-only messages as SMS.

Difference between SMS and OTT applications

OTT applications are another messaging solution. And, in most cases, they offer additional functionality over SMS. Typically, most OTT applications are capable of sending multimedia content, just like MMS.
Typically, OTT apps require an internet connection (wired, WiFi, or cellular internet) to work. That’s one of the biggest differences between SMS and OTT applications. We’ll cover how SMS works in depth in the next section, but SMS messages can be sent over standard cell service, without an internet connection.
Additionally, OTT apps are often used as advertising platforms. The multimedia capabilities of OTT applications make these apps well suited to this. It’s great for the businesses that advertise within those OTT apps.
However, advertisements can degrade the end user experience. Also, if you’re a business looking to connect with potential customers, prospects will see advertisements for other businesses during your conversations.
Additionally, the end user must install the OTT application to use that OTT messaging service, which can present some compatibility limitations.
On the other hand, mobile phones almost never require an additional app to send and receive SMS messages. A mobile phone can almost always send and receive SMS messages right out of the box.
Also, SMS communication is a direct connection, without advertisements or anything to disrupt the conversation.
OTT applications have their place. But SMS requires less software and offers a simpler experience for the end user.

How SMS works

SMS primarily transmits information through a standard cellular connection. In most cases, SMS messages don’t require an internet connection to send, which is one reason why SMS messages are only capable of transmitting text.
When you send an SMS message, the message gets transmitted from the sending device to the nearest cell tower. That cell tower passes the message to an SMS center (SMSC). Then the SMSC forwards the SMS message to a cell tower near the receiving device. Lastly, that tower sends the message to the recipient’s device.
All this can be achieved using the same cellular infrastructure that cell phones use for phone calls. That’s why no internet connection is required, so long as you have cell service.
Also, using this established cellular network is why SMS messages are compatible with so many devices. The technology required for this connection is relatively simple and can be built into just about any device.
However, SMS messages can easily bog down this traditional network, since it’s designed for voice communication. That’s why most carriers have limits on how many SMS messages you can send at a time. Without send limits, SMS centers can get backed up, which causes delays in SMS message transmission.
Even with the limitations, though, SMS is still an excellent channel for all sorts of business communication.

What is SMS integration?

In short, SMS integration is embedding SMS messaging into a website or other customer-facing asset. SMS integration automates as much of the process of sending messages as possible. In short, SMS integration is having a computer send messages rather than having a human do it manually.
Typically, SMS integration is achieved by using an SMS API (Application Programming Interface) to connect SMS message sending software to other business systems and applications. That way SMS messages can be initiated by those other business systems and apps, rather than the SMS messaging software itself.
This automation is why SMS integration is the best way to send bulk SMS messages. If you need to send out hundreds or thousands of messages, manual text messaging is not an efficient option.
SMS integration is the most efficient way for businesses to use SMS messaging for customer communication in contexts where a custom message is not required. Of course, a proper SMS integration doesn’t interfere with manual SMS messaging, where it’s necessary.
With SMS integration, businesses can use computers to send SMS messages, where it’s most efficient (bulk SMS messaging, automated customer service responses, and so on). But a human can still send messages when it’s required.

SMS pros and cons

SMS messaging works very well in many contexts. However, it’s not perfect for every context. We’ve alluded to them. But SMS has its limitations.
These are the ups and downs of SMS messaging.

Advantages of SMS

  • SMS is one of the most common messaging services in the world. About 5 billion people in the world have some way to send and receive SMS messages.
  • SMS offers efficient mass communication. It’s easy and affordable to send an SMS message or hundreds or thousands of recipients, if you use the right SMS software and carrier service.
  • People read most of their text messages. Most marketing texts get opened within 3 minutes. And SMS messaging boasts a 99% open rate.
  • SMS messaging offers a personalized experience. It’s easy to customize an SMS message and add personalized details to make your messages more friendly, even in SMS marketing.

Disadvantages of SMS

  • There’s limited space in an SMS message. SMS messages have a 160 character limit. If you send a message that’s longer than 160 characters, it will automatically get broken up into separate 160 character messages, which can easily blow up someone’s phone, depending on how long your original message is.
  • There are privacy and data protection laws that you must comply with when you send marketing SMS messages. Fines for violating data protection laws can be a bit steep. But you can avoid them with proper compliance procedures.
  • People can be suspicious of unsolicited SMS messages. Text scams have become more popular as SMS has become a ubiquitous communication media. It’s important to craft marketing SMS messages carefully to be clear about who’s sending the message and why they’re sending it. This helps ease people’s suspicions about an unexpected text.

When to choose SMS or MMS

Since SMS isn’t ideal for everything, it’s important to know where SMS is an ideal method of communication. And there are contexts where SMS is a great way to connect with people. In cases where SMS is not ideal, MMS is often the better option.
The basic criteria for determining when you should use SMS or MMS is based on what sort of content you need to include in your message.
If you need to send something other than text—images, videos, audio—you’ll have to use MMS. If you can accomplish your goal with just text, SMS is the better option.
Here are a few use cases for SMS and MMS to illustrate our point.

Marketing outreach (SMS and MMS)

Marketing is one of the most common business use cases for SMS and MMS.
Both SMS and MMS work well because you can send quick, personalized messages that are quick to read (and very likely to be read, given the incredibly high open rates of SMS). And you can include links in your SMS and MMS messages, which are super easy to click on.
If your marketing messaging requires some sort of multimedia like images or videos, you can use MMS to deliver a more engaging message. This works especially well for product launches, sending coupons, and virtual gifts, where it’s more enticing if you can show the product or gift right there in the message.
But a simple text message can also be effective, especially if you’re just looking to get someone to click-through on a link.
Ultimately, though, marketing is one area where you might choose MMS over SMS, given the influence that good visuals can have in marketing messages.

Taking orders (SMS)

One of the most innovative SMS use cases is enabling customers to place orders by sending SMS messages. It’s a convenient and seamless ordering process, which no doubt has increased order volumes for the businesses that have implemented it.
And, given the rise in demand for delivery, take out, and curbside service, taking orders through SMS is a smart way to ensure that your business is capable of meeting the needs of your customer base.
All this is good. But sending visuals isn’t all that necessary for simply taking orders. SMS is the most efficient messaging service for something like taking orders via text.

Customer support (SMS)

SMS is an outstanding way to augment your other customer support channels.
Many customer support issues can easily be resolved with a few text messages. That can eliminate a lot of time spent on hold or waiting for an email response. And faster response times means better customer satisfaction.
However, not every customer service issue can be taken care of through text. In cases where the problem can’t be addressed through SMS messages, you can use text messages to streamline the process of offering customer support over the phone or through email.
You can use SMS to collect information about the customer’s problem. Then you can pass that information to the customer service representative who ends up talking to the customer on the phone or via email, which makes the resolution process faster and easier.
Additionally, using SMS to set up a time to call the customer—rather than making them wait on hold—is a massive improvement over the traditional experience of calling a customer service center.
Using SMS for customer support is a great way to improve your customer experience and make life easier for your customer service teams. And, as you probably noticed, the multimedia capabilities of MMS aren’t a big necessity here.
Most of the time, it will be best to stick with SMS for customer support use cases.
There are more ways to use SMS and MMS. But these use cases demonstrate how you might evaluate your goals to determine if you should use SMS or MMS. But—spoiler alert—SMS will work for most things that you’d need to do with text messaging.

Get started with Telnyx SMS

Ultimately, SMS is an amazing tool for communicating with customers, no matter what message you need to send or what you need to help customers with.
Need to get started using SMS in your business? Learn more about SMS integration with the Telnyx SMS API, or get in touch with our team if you have questions.
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