I have 3G turbostick connection for internet no modem is used. Why do I not get a network connection by going from stb to network card in computer with the cat5 cable
You have to establish a bridge. Essentially your incoming signals require one part of the hardware, in this case the hardware of the special stick gets the signals in. You should bridge it to the network card and you should be able to connect. It is a somewhat difficult task. I have not doen it myself in that way. Plymouth and John Johnatheniel are the experts.