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SMS Overview

About Short Message Service

Colloquially known as “text messaging,” Short Message Service (SMS) uses standardized communications protocols to allow web applications, mobile devices and text-enabled landlines to send and receive typed messages.

All messages are delivered with a registered code for routing and tracking purposes. Depending upon route and country, the supported sender ID type will vary.

Quick Facts

  • Message Length: Standard, plaintext SMS in the U.S. have a max limit of 160 characters per message. This limit varies by handset, country and message content.
  • Concatenation: Some carrier networks support concatenation, which shortens the length of an individual message and chops it into segments, but stitches the content back into a single message for the end-user’s easy reading.
  • Message Content: Characters can be letters, numbers or an alphanumeric combination. Non-text based SMS (such as binary) are also supported.
  • Delivery Status: Due to the nature of store-and-forward technology, it is possible to receive notification of a message’s arrival at various stages in its delivery process.
  • Consumer Reach: All end-users whose mobile devices support SMS can participate in SMS messaging. There are more mobile phones on planet earth than any other electronic device.
  • Reliability: Mobile users can receive SMS messages even when they can’t get phone calls or access mobile data (like emails) because SMS are sent over the carrier’s own dedicated control channel. This makes SMS the ideal form of information relay during disasters.

Example Use Cases

Just a few common examples of SMS use cases include:

  • Account balance updates
  • Customer feedback surveys
  • Live Q&A
  • Loyalty & promotional deals
  • Marketing
  • One-time password conveyance and 2FAuthentication
  • Product recommendation and selection
  • Reminders, alerts and notifications
  • Reservation confirmations & updates
  • Service notifications


The players in the mobile ecosystem don’t want text message content to suffer the same fate as email, many of which go unread due to an overload of unwanted commercial content known as “SPAM.” To protect the efficacy of SMS communication, wireless carriers, service providers and regulators aim to protect consumers through anti-SPAM filters, registration requirements and industry best-practice vigilance. Beyond the industry itself, governing bodies also have a role in protecting consumers. The U.S. FCC’s Telephone Communications Protection Act (TCPA) and Canada’s Anti-Spam Legislation (CASL), for example, require all commercial messages receive consent prior to sending messages to end-users. Due to the abundance of North American messaging stipulations, you can find many articles here on Aerialink Documentation dedicated to the topic of U.S. and Canadian carrier compliance, certification and best practices.

SMS Technology

Store and Forward

SMS is a “store-and-forward” service. This means that before messages arrive at the destination handset, they are first routed through an SMSC–a Short Message Service Center. Networks, carriers and aggregators who support text messaging have one or more SMSCs to serve this function. If the mobile device is powered off, has a weak signal, is out of range or otherwise unavailable when the SMSC attempts to forward the message, the SMSC will store the message and continue to retry sending the message until the end user receives the message or the retry period expires.

The reception of an SMS does not interrupt the mobile user’s voice calls or data usage. While those features require the use of a dedicated radio channel, text messaging utilizes a signaling path that bypasses the radio channel and its traffic clutter.

Network Technologies

The three primary wireless network technologies–GSM, CDMA and TDMA–all support SMS. GSM is the most widely used wireless technology in the world, with a market share of more than ninety percent.

Because these technologies are configured at the network operator level, differing configurations can cause variances in the behavior of SMS delivery. The specs and standards supported by the technologies also differ, but the delivery success of plain-text SMS remains very high.