Unstructured Supplementary Service Data (USSD) is a protocol used by GSM cellphones to communicate with their service provider’s computers. USSD can be . Unstructured Supplementary Service Data (USSD), sometimes referred to as ” Quick Codes” or USSD can be used to provide independent calling services such as a callback service (to . GSM (ETSI EN , V) Specification (USSD) Stage 3 – 3GPP; USSD Technology and packet flow in GSM network. USSD Call FLowThere are two types of USSD — 1. Network Initiated – Push Mode 2. User Initiated – Pull Mod.

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USSD codes, also known as short codes, are simple to use. It is charged on a per vall basis and is more economical than SMS. On the one hand, it holds out the prospect of adding convenience for accessing banking and payment services to customers.

Process unstructured SS request.

T is number of uxsd for the No Reply Uussd Timer, default is 20 seconds if not specified. USSD is an excellent choice for roaming with mobile prepaid service, which utilizes the USSD connection to originate a call while roaming. The application can also be a hyperlink to an internet site or information stored locally in the Service Application System.

Although many of these USSD services are still in the nascent stage, this technology has a huge potential for growth.

Unstructured Supplementary Service Data – Wikipedia

Thus, when roaming in another network, dialing a Usd string will always route the application on the home network. The processing happens in the same way as explained above, but the supporting USSD application server may be different. Once the call is established between roamer and intended called party, the HPLMN monitors the service usage against the available balance in real time.

This site uses cookies. The possible error types are as ussv. To avoid this, the GSM encryption needs to be made more robust, much like how internet banking has evolved over the years.


USSD Call Flow – GSM & BEYOND ……

For many operators, prepaid now represents up to 80 percent or more of their subscriber base. Notify me of new posts via email. On some pay as you go networks, such as Tesco Mobileonce a user performs an action that costs money, the user sees a USSD message with his or her new balance. The connection remains open, allowing a two-way exchange of a sequence of data. Thank you in advance.

However, there are some rare cases where network operators implement a billing system. This indicates that the receiving entity does not support the alphabet indicated in the USSD operation.

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There was no session held between the handset and the application; it was just like SMS service. Figure 1 shows the USSD network architecture. The possible error types are as follows: The receiving entity, on unsuccessful outcome of the service, returns a user error. In the core network, the message was delivered over MAP. Your ussd application then responds to the request, and Ussd gateway goes ahead and displays your content to the user Below is a another diagram to help understand the concept.

After verification, the prepaid roaming application in the HPLMN initiates a call to the destination subscriber and then initiates another call to the roamer. Because the MSC initiated the transaction, it is also responsible for controlling the transaction. Starts with basic stuff and then go in to architecture and how it works. The length and content of a USSD string is very flexible.

In other words, an SMSC is not present in the processing path. USSD can therefore be expensive in terms of its resources assigned. Clearly, the positives of USSD far outweigh the negatives. Because the USSD technology uses the existing SS7 protocols, significantly less investment is needed in the the network.

An example of such an application could be as follows: Email required Address never made public. The introduction was carried out in multiple phases. There are many ways to implement prepaid roaming. USSD can be used for WAP browsing, prepaid callback service, mobile-money services, location-based content services, menu-based information services, and as part of configuring the phone on the network.



Network operators often use USSD to query users about the network to receive a fast response. Messages sent over USSD are not defined by any standardization body, so each network operator can implement whatever is most suitable for its customers.

The USSD application responds by sending an updated balance and ends the session. USSD-based solutions can help operators balance the trade-off involved in keeping service levels high and costs low. The MS can also terminate a dialogue by sending a release complete message. Please help improve this section or discuss this issue on the talk page. This parameter contains the alphabet and the language information used for the unstructured information in a USSD operation.

Figure 2 explains the elements of the mobile network and the communication protocols they use. It can be concluded from this discussion that the USSD technology can go a long way in improving the living conditions of the poor.

Unstructured Supplementary Service Data

Short codes are standard messages pre-defined in the USSD platform. This parameter contains the cll and the language information used for the unstructured information in a USSD operation. USSD is increasingly being adopted to develop interactive applications like mobile chatting, roaming with prepaid service, callback service, simultaneous software up-gradation of huge customer base, prepaid recharge, mobile banking, etc.

A billing mechanism for USSD services is not implemented in most cases. USSD services reside as applications in the mobile network.