Switches the ports of a USB hub -- an ExSYS 16-port managed hub over its internal FT232 line, or any hub that switches its own ports, through hub-class requests (FreeBSD for now) -- and for the boards on it speaks SWD through openocd and reads their consoles over USB CDC. Which board sits on which port, and which ports must never lose power, is read from a configuration, so the tool switches the bench it is told about and nothing else. What a console's lines mean is left to a tally loaded at run time.