Serial Communications in Unix Why serial? Serial communications are less common outside of USB on modren computers, but serial in the form of I2C and SPI are still very common in embedded systems. When working with micro-controllers I often find myself needing to send data over a noise reistant medium and RS485 is very relible in electrically noisy enviroments. Lets take a look at method in quesion Modbus When it comes to connecting to multiple devices from a single serial connection the options often used by a lot of projects are I2C, SPI with SS and CAN.