What Is USSD?

The old messaging technology that's making a comeback

By
Nicholas Congleton
Nick Congleton
Nicholas Congleton
Writer
  • William Patterson University
Nick Congleton has been a tech writer and blogger since 2015. His work has appeared in PCMech, Make Tech Easier, Infosec Institute, and others.
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Updated on August 4, 2020

USSD stands for Unstructured Supplementary Service Data. Essentially, it’s another messaging protocol, similar to SMS (Short Message Service), which most people use daily to send text messages. Like SMS, USSD is a product of a time before smartphones, when phones needed a way to communicate without full-blown applications. Here's what you need to know about it.

What Is USSD?

USSD is a communication protocol that utilizes codes made up of the characters available on a mobile phone. USSD messages can be up to 182 characters long, and they create a real-time communication session between the phone and another device, usually a network or server.

The real-time aspect of USSD is made possible because communication is continually left open between devices. This makes it easier to exchange data.

What Can USSD Do?

USSD is all about opening a line of communication and sending data while the line is open. It can only send messages while the connection is established, so it’s not quite the same as a text messaging service.

All USSD connections start more or less the same way. You send a message to code. The code is a combination of numbers and special characters. Your phone carrier uses that code to route you through to the correct service. When you establish contact with the service, you have access to the information, data, updates, or simple applications it provides.

How Is USSD Used?

One of the most common uses of USSD comes from prepaid phones. When you purchase one of these devices, you can send a message to a code number to check on your balance. The phone provider uses the same connection to provide real-time updates.

It’s also possible to deliver updates from social platforms over USSD to receive updates as soon as possible.

Then, there are applications built over USSD. You can dial a USSD code and get back a menu. You can use that menu to do just about anything, from adding more time to your prepaid phone to requesting information or even paying for services. USSD applications are actually very popular in some places, like Africa.

USSD also has applications in the banking world. Its quick and lightweight nature makes it ideal for balance inquiries and transfers. Sending a message over USSD is faster than a mobile banking app, and it can be done from virtually any cellular device.

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