Unstructured Additional Services Data (USSD), sometimes referred to as "Quick Code" or "Feature code", is the communication protocol used by the phone GSM mobile to communicate with the mobile network operator's computer. USSD can be used for WAP browsing, prepaid callback services, mobile-money services, location-based content services, menu-based information services, and as part of phone configuration on the network.
The USSD message has a length of up to 182 alphanumeric characters. Unlike Short Message Service (SMS) messages, USSD messages make real-time connections during USSD sessions. The connection remains open, allowing a two-way swap from the data set. This makes USSD more responsive than services that use SMS.
Video Unstructured Supplementary Service Data
Usage
When a user sends a message to the phone company's network, it is received by a computer dedicated to USSD. The computer response is sent back to the phone, generally in a basic format that can be easily viewed on the phone's screen. Messages sent via USSD are not specified by the standardization body, so each network operator can implement whatever is most appropriate for its customers.
USSD can be used to provide independent call services such as callback services (to reduce phone charges while roaming), enhance mobile marketing capabilities or interactive data services.
USSD is generally used by prepaid GSM mobile phones to inquire about available balances. The vendor's "check balance" app hides the user's USSD protocol details. On some pay as you go network, such as Tesco Mobile, once the user performs actions that require money, the user sees a USSD message with their new balance. USSD can also be used to recharge the balance on the user's SIM card and send a one-time password or PIN code.
Some operators use USSD to provide access to real time updates from social networking websites like Facebook and Twitter. Wikipedia uses USSD to post articles to multiple feature phones.
USSD is sometimes used in conjunction with SMS. The user sent a request to the network via USSD, and the network replied with a receipt acknowledgment:
- "Thanks, your message is being processed. The message will be sent to your phone."
Furthermore, one or more SMS messages ending in mobile communicate the status and/or result of the original request. In such cases, SMS is used to "push" replies or updates to the handset when the network is ready to send it. In contrast, USSD is only used for command-and-control only.
Maps Unstructured Supplementary Service Data
Technical details
Most GSM phones have USSD capability. USSD is generally associated with instant messaging services or real-time. There is no store-and-forward capability, as is typical of other short-message protocols such as SMS. In other words, SMSC is not on the processing line.
USSD Stage 1, as specified in GSM 02.90, only supports manually-executed operations ("drag"). In the core network, messages are delivered via MAP, USSD Stage 2, as specified in GSM 03.90. After entering the USSD code on the GSM handset, replies from the GSM operator are shown in a few seconds.
Format
Typical USSD messages begin with an asterisk (*) followed by a digit consisting of commands or data. Numeric groups can be separated by additional star signs. The message ends with a number sign (#).
USSD mode
Initiated by mobile device
- USSD/PULL or USSD/P2A
- when the user calls the code, e.g. * 139 # of GSM mobile handset
Network starts
- USSD/PUSH or USSD/A2P
- when the user receives a push message from the network; mainly used for promotion services
Code Listing
The code below is not USSD code , but the MMI Additional Services code; they are standard so they are the same on any GSM phone. They are interpreted by the handset first before the appropriate command (not the code itself) is sent to the network. These codes may not always work when using the AT interface; there is a standard AT command defined for each of these actions.
BS is a carrier type service, some valid values ​​are:
- 11 for voice
- 13 for fax
- 16 for SMS (valid only for restrictions)
- 25 for data
- & lt; leave empty & gt; for all.
T is the number of seconds for No Condition Condition Condition, the default is 20 seconds if not specified.
See also
- USSD Gateway
- Ultra Mobile Broadband
- Additional service code
- Call forwarding # Mobile phone.28cell.29 phone details for Call forwarding code for mobile
- The SIM Application Toolkit
References
External links
- GSM Specs 04.90 (ETSI EN 300 957, V7.0.1) (USSD) Stage 3 - 3GPP
- USSD technology and packet flow on the GSM network https://www.facebook.com/USSD2
- 3GPP TS 22.030
- GSM Features Code
- Unknown GSM Features
- What's the difference between USSD, MMI, and SS codes?
Source of the article : Wikipedia
0 Comments