Shulou(Shulou.com)06/02 Report--

Editor to share with you what ussd refers to, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to understand it!

Ussd, that is, unstructured supplementary data service, is a new type of interactive data service based on GSM network. Use the mobile phone keyboard to input some numbers or symbols that have been predetermined by the network, such as [* #], and then press send, that is, the dial button, you can send a command to the network, and the network can choose the service you need to provide you according to your instructions.

This is a problem caused by smart dialing. The number you dial begins with * and ends with #, and the phone thinks you are sending USSD code, so it shows that the USSD code is running. If you use a mobile network that supports USSD, an error message will be returned, and if not, you will die there all the time.

USSD (Unstructured Supplementary Service Data), unstructured supplementary data service, is a new type of interactive data service based on GSM network.

When you use your mobile keyboard to enter some numbers or symbols that have been predetermined by the network, such as * #, and then press send, that is, the dial button, you can send an instruction to the network, and the network will choose the service you need to provide you according to your instructions.

Compared with short message, GPRS and WAP, its feasibility and advantages in industrial application are compared. Taking the wireless remote monitoring system successfully operated by CLP 50 in Urumqi as an example, this paper describes the system structure, interface protocol and communication flow of USSD in industrial application.

Extended data:

USSD features:

1, call statu

Using independent dedicated control channel SDCCH (Stand-alone Dedicated Control Channel), the data transmission rate is about 600bps; while in non-call state, USSD uses fast auxiliary control channel FACCH (Fast Associated Control Channel), which is about 1kbps, which is higher than the SMS transmission rate.

Users can only use WAP in non-calling state, and the data can be exchanged through the traffic channel TCH (Traffic Channel). The transmission rate of WAP is about 9.6 kbps. WAP's response time is slow, and it needs special WAP mobile phone support.

2, conversational process

Always maintain the call connection, provide a transparent channel, and do not store and forward; while SMS has no session channel in the physical bearer layer, it is a store-and-forward system, and users need to carry out multiple sessions to complete a query. Because USSD is similar to GPRS, it maintains a session process in the interaction, and each data transmission does not need to re-establish the channel, so the USSD system responds immediately to the user's call request, which greatly speeds up the response time. The main response delay has been transferred to the application server, and the response time is faster than the short message.

3, interactive session

Can provide intuitive menu operation, convenient for users to use, in an information service, only need to dial the service number, you can follow the menu prompts for the next operation, you can establish a portal similar to WAP to provide telecom value-added services.

4, user groups

In the industrial environment, the cost of using USSD is low in the case of small traffic and only a few K of data at a time, while GPRS is suitable for data transmission with large amount of information because of its wide conveyor belt.

Most of the mobile phones on the market support USSD service

In industrial applications, most communication modules or chips with SMS and GPRS functions also support USSD services.

5, system structure

The monitoring center establishes TCP/IP connection with USSD platform through Internet or special line, USSD transmission terminal establishes wireless connection with USSD platform through GSM public network, and establishes a data communication channel with GSM network, monitoring center and field monitoring unit through USSD platform.

There is database backup data in the mobile USSD platform. Besides the application platform, the monitoring center can also have wired browsers for monitoring. Through the GSM network and USSD platform, wireless browsers and mobile phones can also establish contact with the monitoring center.

The above is all the contents of this article "what does ussd mean?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.