Hi, i have an center communication for GPS and generic GPS listenner, with standar protocol comminication, this will let us make an simple JSON to communicate to center and send commands from JSON to device in her protocol.
this all writed on java.
I just can say GPS listenners and JAVA is my main skill.
if you only need listenner and to stock data the price is 500USD by protocol hard, binary, AT and 350USD by normal protocol.
And if you need center for communicate from WEB page or another device is an addon with 600USD (you only need pay it an time).
And sorry about my english, is't my native language... have good day.