yes having two ports only ttyS4 and ttyS5 i am not using any usb to serial converter i am directly connecting with serial port only .....i have tried terminal example its giving the permission error means sudo permission .....
Are you sure you really have 4 serial ports? Which kind of machine have you got?
In some case, with a beaglebone board for example, you have to enable the third and fourth serial port with a special kernel parameter.
@mrdebug
I have only two serial ports i am connecting slot machine to my desktop computer.....need to connect from desktop to slot machine i am struggling to open the serial port please help me i have added like this
ubuntu 16.04 LTS ,i opened serial port now if i choose the run in terminal its opening please help how to set sudo password in qt instead of choosing run in terminal directly need to open