Problem getting M4 to comunicate over rs232

Hello.
I have an M4 serial4631 and I cannot get it to work EMP shows not connected.
Laptop has physical com port, I made a dualboot system so freedos would load seperately of windows.
I have tried few diffrent versions of EMP, 6.12 / 6.13 / 6.20d
Should I have to configure baudrate and other comunication settings beforehand, or defaults should work ?
I tried also dosbox to run it, but it does not connect to ecu, so I am starting to wonder if the ecu itself is alive?
I measured if it gives out +5v on pin4 and it does
In your experience, have there ever been an error with the ecu itself ?
I have an M4 serial4631 and I cannot get it to work EMP shows not connected.
Laptop has physical com port, I made a dualboot system so freedos would load seperately of windows.
I have tried few diffrent versions of EMP, 6.12 / 6.13 / 6.20d
Should I have to configure baudrate and other comunication settings beforehand, or defaults should work ?
I tried also dosbox to run it, but it does not connect to ecu, so I am starting to wonder if the ecu itself is alive?
I measured if it gives out +5v on pin4 and it does
In your experience, have there ever been an error with the ecu itself ?