interact with trix box, through a program

Hi there,
I am new to the forum,

how it is possible to develop an application that can interact with the TrixBox, in other word to function like the X-Lite software,
To be able to register with the PBX, to invite another party to a call, in other word to contact to the server via the program,
I have read about the asterisk-java, and the asterisk
I have little knowledge about network programming in general
but I need to understand it well,
any help please , links , tutorials , opinions
I hope I made my self clear, if not please let me know so I add more explanation

thanks in advance