What Is USSD? Unstructured Supplementary Service Data
USSD (Unstructured Supplementary Service Data) is a Global System for Mobile Communications (GSM) protocol that is used to send text messages.
USSD is similar to Short Message Service (SMS). USSD uses codes made up
of the characters that are available on a mobile phone
.
When a user sends a message to the phone company network, it is
received by a computer dedicated to USSD. The computer's response is
sent back to the phone, generally in a basic format that can easily be
seen on the phone display. Messages sent over USSD are not defined by
any standardization body, so each network operator can implement whatever is most suitable for its customers.
USSD can be used to provide independent calling services such as a callback service (to reduce phone charges while roaming), enhance mobile marketing capabilities or interactive data services.
USSD is commonly used by prepaid GSM cellular phones to query the
available balance. The vendor's "check balance" application hides the
details of the USSD protocol from the user. On some pay as you go networks, such as Tesco Mobile,
once a user performs an action that costs money, the user sees a USSD
message with his or her new balance. USSD can also be used to refill the
balance on the user's SIM card and to deliver one-time passwords or PIN codes.
Some operators use USSD to provide access to real-time updates from social-networking websites like Facebook and Twitter.[2] Wikipedia uses USSD to send articles to some feature phones.[3]
USSD is sometimes used in conjunction with SMS. The user sends a
request to the network via USSD, and the network replies with an
acknowledgement of receipt:
- "Thank you, your message is being processed. A message will be sent to your phone."
Subsequently, one or more mobile terminated SMS messages communicate the status and/or results of the initial request.[4] In such cases, SMS is used to "push" a reply or updates to the handset when the network is ready to send them.[5] In contrast, USSD is used for command-and-control only.
USSD
USSD (or Unstructured Supplementary Service Data) is an interactive,
menu-based technology communication protocol available on every
GSM-enabled mobile device.
It is a session-based text communication without a store-and-forward
mechanism (unlike SMS) that is practical for interactive communication,
such as banking or education.
USSD messages can have up to 160 alphanumeric characters and the time
it takes from a request to a response is 2 seconds while it takes 6
seconds for an SMS to reach a mobile phone.
What is the difference between USSD and SMS?
While SMS is a store and forward technology, USSD texts and
interactions are not stored on the mobile phone. SMS content remains
stored in the mobile phone memory.
Examples of USSD usage
Some examples of service usage are airtime top-ups, “please call me” services, balance checking and mini statements delivery.
What about USSD short codes?
USSD short code format is defined by the * and # signs at the beginning and the end of the series of digits.
There are three types of USSD short codes available. The standard
rate USSD short code is charged the standard fee for the USSD menu usage
by the end-user. Reverse-billed short codes are free for the end-user.
Premium rate USSD short codes are charging the end user a premium price
for short code triggering. Generally, USSD short codes are either
reverse-billed or standard rate.