RPI2-GPIO

[MarkHaysHarris777]

hi mus1c,  the answer to your question depends on whether the serial console has been enabled. It also depends on what you're going to use the PI end of things for. 

The Pine board is better, and the system is more consistent , and especially from a serial point of view. On the Pine uartx is ttySx ie  uart0 is ttyS0

On the PI the device is either serial0  or  ttyAMA0;  and this depends on whether serial is enabled and whether the serial console is enabled. You will want to read the PI forum posts (mine and others) and make sure you understand how to enable serial comm on the PI. 

You can use raspi-config to disable the serial console on the PI. You may also manually edit the config and command line files. Ultimately, if you want to use the serial uart pin(8) & pin(10) GPIO14 &GPIO15 for serial comm you will need to disable the serial console. 

The device is either serial0 , or ttyAMA0  depending.