Emulating physical line break
On the “All” tab, select a pair of ports you want to emulate a line break for, then click the “Break” button:
After that, all incoming signal lines (DCD, DSR, CTS, RI) will be dropped, and data from one port won’t be transferred to another one.
Restoring the connection
On the “All” tab, select the pair of ports you’ve emulated a line break for, and click the “Restore connection” button: