If you are working on telephone solutions, please check
out the Ozeki VoIP SIP SDK.
It can be used to create:
- Adobe Flash video phone
- Silverlight video phone
- Web to web calls
- Web to VoIP calls
Custom SIP clients:
- Silverlight SIP VoIP client
- Flash SIP VoIP client
- C# .net SIP VoIP client
- ASP .net SIP VoIP client
- Web based SIP VoIP client
Custom VoIP solutions:
- VoIP SIP softphones
- VoIP call center clients
- VoIP IVR systems
- VoIP predictive dialer systems
- VoIP auto dialer systems
- VoIP call assistant
- VoIP call recording systems
- VoIP intercom solutions
Common protocols - Premium-rated SMS services
Mobile service providers often allow 3rd party
content providers to create mobile services using premium rate
SMS messages. These services may be games for prizes, tests,
data services etc. Premium rate SMS messages make it possible to
collect money from users of these value-added services. Since the
amount of money collected is rather 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).
services work in the following way:
The person who would like to use the premium
rate service sends an SMS message to a premium rate phone number.
When the SMS arrives in the Short Message Service Center
(SMSC) of the service provider, the SMSC recognizes that the
destination phone number belongs to a "content server". As the
next step, the message is transferred to a content provider's
server over 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 over 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).
Figure 1 - Premium-rated 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 a reply
SMS message must be sent back to acknowledge the service request
within a limited response time (usually in 2 minutes).
Some useful information:
Premium rate SMS prices cannot be chosen freely.
In most cases the content provider must select a price offered by
the GSM service provider.
rate phone number can run several services, but can only operate with
It is not possible to send/receive premium rate
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 rate 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 rate SMS services 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 price phone numbers. They often use a special prefix,
such as 06 90.
If there is no response to the premium rate SMS, the Mobile
Service provider does not charge the customer.