If you installed the full Anaconda distribution of Python, PySerial comes pre-installed.
To use the PySerial package with Python, PySerial first needs to be installed. USB and is built upon and extends the original serial communication interface. Serial communication protocol predates the USB specification used by computers and other pieces of hardware like mice, keyboards, and webcams.
Serial communication is one of the oldest computer communication protocols. PySerial provides an interface to communicate over the serial communication protocol. PySerial is a useful package for problem solvers because it allows us to exchange data between computers and pieces of external hardware such as voltmeters, oscilloscopes, strain gauges, flow meters, actuators, and lights. A computer running Python with the PySerial package installed can communicate with external hardware. PySerial is a Python package that facilitates serial communication. Problem Solving with Python Book Construction
