Siemens S7-300 User Manual page 26

Run the VCOMM virtual serial port software on the PC, set the simulated virtual serial port on the
PC. Select VCOMM as Server mode, accept client connections. Choose to use the device detector
to create a virtual serial port.
Add a new virtual serial port, the monitoring IP address = PC IP address, client mode device try to
connect the port = VCOMM software port, this is 8000.
Click OK and exit the software and re-run VCOMM, the server VCOMM will wait the connection
of client ETH Adapter CN,then it will create a new serial port COM3 after establishing the
connection, and it will appear in the Device Manager of the Windows system, then you choose this
serial port in your application software, such as STEP7.
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