Common protocols - Premium rated SMS services

Mobile Service providers often allow 3rd party content providers to create mobile services using premium rate SMS messages. The services can be games for prizes, tests, data services.

Premium rate SMS messages make it possible to collect money from the users of these value added services. Since the amount of money collected is very small, these services are often referred to as micropayment services.

Today's most popular premium SMS services are downloadable games, logos, ringtones, background pictures and information services (e.g.: weather, news, programs).

How prremium rated sms service works

The person who would like to use the premium rate service, sends an SMS to a premium rate phone number. When the SMS arrives into the Short Message Service Center (SMSC) of the service provider, the SMSC recognizes that the destination phone number belongs to a "content server". As a next step, the message is transferred to a content provider's server through a TCP/IP connection. The content provider's server receives the SMS messages and generates a response SMS according to the implemented business logic. The response SMS travels back to the SMSC for transmission through TCP/IP just as the request SMS was transferred to the content server. In most situations the content server and the SMSC communicate over the Internet (Figure 1.).

premium rated sms service architecture
Figure 1 - Premium rated sms service architecture

The business logic of the content server can be simple or complex. One of the most common solutions is based on content interpretation. A simple algorithm compares the incoming message text to a set of keywords, and generates a response based on the keyword. Another common application collects the phone numbers of the received messages and uses these phone numbers to provide periodic information services, such as traffic report or weather report every morning. There are many other types of solutions as well. One thing they have in common, is that in every case an SMS must be sent back to acknowledge the service request within a limited response time (usually in 2 minutes).

Some useful facts:

  • The premium rate SMS prices cannot be chosen freely. In most cases the content provider must select a price offered by the GSM service provider.
  • One premium rate phone number can run several services, but can only operate with one price.
  • It is not possible to send/receive premium rated SMS messages using SIM cards of foreign countries. It means that there is no such thing as premium rate roaming.
  • When creating a solution, it is important to check if premium rated messages can be sent to our service from every GSM network in the country. Sometimes it is necessary to sign a contract with all GSM providers independently.
  • Premium rated SMS service cannot be operated using a GSM phone attached to the PC with a phone-to-pc data cable.
  • Premium rate SMS service phone numbers are often different from normal priced phone numbers. They often use a special prefix, such as 06 90
  • If there is no answer for the premium rate SMS the Mobile Service provider doesn't charge the customer.

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