This Knowledge Base article details the three on board serial port types available

This Knowledge Base article details how to configure the primary serial port ttyAMA0 on the MyPi Integrator Board.

This Knowledge Base article details how to configure the secondary serial port ttyS0 on the MyPi Integrator Board .

This Knowledge Base article details the work-around for solving baud rate issue when using the secondary Raspberry Pi UART (ttyS0) on the Compute Module 3/3+

This Knowledge Base article details the software fix needed for comms problems with UART0 (ttyAMA0) when running Raspbian Linux Kernel 4.9+