Dear 🙁
I ahve a old DOS application that work with serial port.
The application works does not work well because the serial port is write and read directly by interrupt.
I have look in the source that the serial port is read by polling and this is a timing problem.
Moreover my serial protocol use the nine-bit synchronization and dosbos some time don't recognize correctly the nine-bit (parity).

There is a plug-in o other solution for work with serial at low level ?

Thank all in advance

Stefano