how can do that
please any one can help me about send and recieve packets by serail port the pakeck that i need to send is in hex to controll some thing how can do this in vb.net how can do like this design in the picture below
please help me
Read here: http://www.codeproject.com/Articles/5131/COM-port-made-simple-with-VB-NET or here: http://msdn.microsoft.com/en-us/library/system.io.ports.serialport.aspx
Your picture doesn't help us. Next time try including source code and the point you are having problem.