I have been working with OpenGTS for about 3.5 years, and have customized it many times.
The TK103 would be a good choice since it has been around for quite sometime, and the code to communicate with it comes with OpenGTS.
OpenGTS is written in server side Java by the way, there is no PHP code in it at all.
Do you have an English translation of your requirements?
Regards,
John H. Ward, Jr.