Setup a USB to serial converter with DOSBox on Linux. Find the device ID for USB to serial adapter, like “/dev/ttyUSB0” if it’s a USB-serial adapter:

ls /dev/ttyUSB*

Allow non-sudo serial port access by adding the username to “plugdev” and “dialout” groups:

adduser $(whoami) plugdev dialout

Logout and login. Edit ~/.dosbox/dosbox*.conf, under [serial] modify the serial1=dummy:

serial1=directserial realport:ttyUSB0

DOSBox should work with serial device on COM1

Reference: DOSbox config manual

If you can’t access a device, ensure the username is in “plugdev” group as noted above, and perhaps try (assuming device is /dev/ttyUSB0):

chmod 666 /dev/ttyUSB0