From SMS Gateway Enterprise Software:
SMS gateway can be used over HTTP SMS connections, ideal platform for SMS notification, SMS paging, two way SMS systems, or for becoming an SMS service provider. SMS Service providers often create SMS services like SMS Voting, SMS Banking, and SMS Games. It supports SMS API for SQL, .NET, ASP, ASP2, VB, C#, C++, Delphi, PHP, JAVA and for OEM vendors. It can be configured as an HTTP SMS Gateway for WEB SMS applications, as an E-mail SMS Gateway for E-mail SMS alerts. For SMS transfer IP SMS protocols and GSM Modem AT commands are used. IP SMS protocols, such as SMPP provide high performance. Good quality GMS modems, such as Wavecom Fastrack, Siemens MC65, TC65, TC35 and Voice GSM modules, such as the Nokia 30 and Option 3G modems can be used to run your most demanding SMS applications.
If it is important to work with a stable and reliable software that provides cost effecting services, Ozeki NG is a good choice.
It is quite expensive though after a short period of time you can save valuable time and money with the operation of the software (it is worth operating)
I use Ozeki NG to operate SMS services with high capacity. My company needed an SMS gateway that is able to operate with large amount of messages without problems in 24/7. Ozeki is able to meet our requirements: it is stable and functions properly. It has a transparent user interface as service provider connections, user's applications, and incoming and outgoing routes are on the same interface. It also supports load balancing and backup routing among others that allow more reliable working.
I could start in small with a GSM modem, and I could sign up for an SMS service later without changing a thing in my app. The software handled all characters perfectly and it did not have a problem with long SMS messages. It is very reliable.
It took me some time to configure it. The routing is very flexible, but takes effort to setup. It is expensive.
I would recommend this software to anybody who want to setup a professional service based on SMS messages. It is high quality. After installation it works without a notice.