Hi, I am working on an VB.Net application which I want to communicate to external device using comm port (Serial Port) . So for that first I am trying to simulate the communication on serial port between two computers using HYper terminal on both the machines. Both these computers are connected on serial port using DB9(f) null modem (Cross) cable. But I dont see any data transfer between these computers. Sometime I am not able to type anything on the Hyperterminal window also. Basically I need to migrate the legacy MSComm in VB 6.0 application to SerialPort in VB.Net 2005. I have checked that hyper terminal settings are correct in both the machines. I am not sure If I am doing anything wrong to simulate this serial port communication between two computers. Any help would be appreciated. Thanks