Beaglebone UART and arduino tx and rx pin

I’ve connected a arduino to BBB by connecting pin 0(rx0) of arduino to pin 24 p9 of BBB and pin 1 to pin 26 p9 of BBB. I need to us UART1 through c++ to send a string from bbb to arduino. Any ideas??

Are the signal levels the same? I don’t think so, BBB is 1.8V logic, arduino is 5V…

BBB is 3.3V.