The Fundamentals of SMS.jpg

Chapter 1:
The Fundamentals of SMS


Before we get into the nitty-gritty of SMS marketing, it’s important to go over a few important details about SMS. That’s why we’ve created this chapter to help you understand what SMS is and what it isn’t. We’ll also go over some things about spam compliance, because we take it very seriously.

With that, let’s dive right in!

What is an SMS?

SMS stands for Short Message Service, often referred to as a text messaging. A singular SMS has a 160 character limit. You also have the option to send up 612 characters in the form of 4 concatenated messages. If you do plan on sending messages longer than 160 characters, we recommend using this SMS Character Counter tool to help you see where your messages will be concatenated.

Text messages are universal, and can be accessed on any mobile phone in the world. More importantly, text messages can be sent and received without a data connection. This can’t be said for data-reliant chat applications like WhatsApp, WeChat, or Facebook Messenger which also require a smartphone.


You might have heard of an MMS, which stands for Multimedia Message Service, but it’s not as commonly used as an SMS.

For the most part, MMS can do almost everything an SMS can. It also offers an extended set of features that SMS does not have. You can deliver a variety of media files, including video, images, gif animations, or audio.

Here’s are the main differences between an SMS vs MMS:

Subject Title Not Available Up to 20 characters
Message Copy Up to 612 Characters
*1-3x Concatenation after 160*
Up to 1,000 Characters
*No concatenation*
Custom Sender ID Available Available
2 Way SMS Available Not Available
Keywords Available Not Available
Unicode Characters Available Available
Website Links Available Available
Unique Link Tracking Available Not Available
Multimedia Files Not Available .jpg, .wmv, .gif, and .mp3
Pricing Based on # of messages Based on overall file size

Since MMS offers more features, it also comes at a much higher cost than an SMS (often 4-5x higher per message). Set-up fees are also often charged on top of these per message sends, which is not common when it comes to SMS.

If you’re interested in learning more about MMS, check out are article on The mystery behind MMS vs SMS marketing.

Shortcodes and Virtual Numbers

When it comes to branding or creating a memorable experience for your customer, dedicated virtual numbers and shortcodes are highly recommended. They add an important layer of consistency and trust for your customers towards your marketing efforts. These numbers can be leased on a month to month basis, and cancelled any time.

Dedicated Virtual Numbers:

There are two types of virtual numbers: shared and dedicated. Shared Virtual numbers belong to a pool of rotating numbers, while dedicated numbers belong to you and only you for as long as you want to lease it. Virtual numbers are also referred to as long codes or response numbers (eg +61 459 333 444). They look like a regular number, and can be used to send and receive SMS messages.

Shared Virtual Numbers:

If you decide to not purchase a dedicated virtual number, a free shared number will often be your default option.

Just like it sounds, they’re shared between other businesses. It doesn’t end there though. The shared number changes from time to time from a pool of rotating numbers. 

Imagine yourself receiving 3 SMS from the same business but each from a different number.


Shortcodes are a short sequence of numbers, typically ranging 4 or 6 digits (e.g. 134568). They can also send and receive SMS, and are commonly used for promotions, voting, and information services. Some countries also require you to send messages only via shortcode, for example - New Zealand.

Spam Compliance

We all know as consumers ourselves, spam is a big no-no.

Spam laws aren’t meant to handcuff your SMS marketing campaigns. In fact, abiding by the spam laws helps you create better campaigns that build trust with your customers.

To be spam compliant, there are few important rules to follow:

  1. Permissions: The recipient must be aware that they opted-in to receive commercial messages from your company
  2. Identify Yourself: By law you must always identify yourself by company either in the Sender ID or within the SMS itself.
  3. Opt-out Option: Give them the option to unsubscribe. As a responsible sender, you must provide an opt-out mechanism. This must be displayed within the SMS, usually on the very bottom of any message. Most SMS platforms will automatically generate this opt-out for you inside your send screen.

That being said, there are organizations that are exempt from the SPAM law in specific countries. For example, in Australia these exemptions include: 

  • Government bodies
  • Registered charities
  • Registered political parties
  • Educational institutions
  • Purely factual messages

Spam compliance is all about doing the right thing for your audience. If you’d like to learn more about building your SMS list the right way, check out our anti-spam policy