Rasbian Serial Console Configuration
By default the base MyPi Raspbian images have the serial console enabled on UART1 (ttyS0)
Start up the board and the following will appear, followed by the login prompt
To disable the serial console you should remove the below from /boot/cmdline.txt
dwc_otg.lpm_enable=0 console=serial1,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
And then run :
# systemctl disable serial-getty@ttyS0.service