Send Command to instrument using TCP/server

Hello All;

I make a Dll to remote control an instrument.

Know i wanna make server application that communicates with client and make the remote control to the instrument

1-I add the .lib and the Dll to the server application.

2-I can open TCP connection to the server.

The problem now is : 

                                 -If i'm correct i have to send command from the client to the server to use the instrument using TCP                                             write, but nothing happen

                                  -Could some one give me an exapmle?

Thanks a lot.