... 2Mbytes flash memory, voltage regulator, 2 channels DB-9 serial port connector, 1 USB connector, switches and LED which ... may not display expected result.Serial interface : 4 serial interface, “1” &”0” are internal serial interface for DS5250, they communicate ... MAX213E linear driver accepts expansion serial port “2”& “3” then add new serial debugging, not occupy internal serial port. Signal put out ...