pySerial API — pySerial 3.4 documentationValueError – Will be raised when parameter are out of range, e.g. baud rate, data bits. SerialException – In case the device can not be found or can not be configured. The port is immediately opened on object creation, when a port is given. It is not opened when port is None and a successive call to open() is required. port is a device name: depending on operating system. e.g. /dev/ttyUSB0 on GNU/
