I can't choose any port name

[AhmetFarukBilgin]

Both in master and salve ı cant choose the port name, what am ı doing wrong ?

[thoblerone]

I have just checked with a recent build of my fork, but it's the same for the original: you can only choose a port number, when the communication mode is TCP or UDP, upon connecting the log window will contain some text indicating the port number.

Only when you are using RTU connection, you have to choose a port name from the available options. The available com ports are queried from your hardware. Open your device manager and the list of available com ports will be the same as in the com port combo box. See

ModbusTool/CommonControls/BaseForm.cs

Line 51 in 2b6764a

private void FillRTUDropDownLists()