I am trying to make Norton Commander on an OLD 286 DOS 6.22 box without ISA or PCI and only one COM port communicate with another Norton Commander that is in a DOSBox on a Ubuntu 18.04.2LTS machine. I cannot get a connection using the Link feature in NC.
To do that I use a serial nullmodem cable. I tested with a third machine that has DOSBox on Windows 10 Pro and that works great(I set Windows COM1 to 38400.). So the DOS end of this setup is tested and works and it also confirms that Norton Commander works fine in a DOSBox, at least if its running on Windows 10 Pro. Also the nullmodem cable is tested in this windows<>DOS test setup so all that is working ok.
The only difference is the Ubuntu machine. I tested with a serial mouse and the correct com port is working and its ttyS0. I redirected the serial port to /dev/ttyS0 and the DOSBox terminal says" Serial1: Opening ttyS0" so that seems ok too. I am member of group dialup and everybody (777) has access to /dev/ttyS0. sudo stty -F /dev/ttyS0 returns "speed 38400 baud; line = 0;" I am at a loss, does anyone have any tips to debug this?