There is a UART port on the 30pin header.

**CON10 - 2x15 pins**
^ Pin Number ^ Net Name     ^ GPIO & Export No    ^ Default Pin State    ^
| 6          | UART_0.RXD   | GPA0.0 (#171)       | I(PUDN) |
| 8          | UART_0.TXD   | GPA0.1 (#172)       | I(PUDN) |

Access device node \\
/dev/ttySAC0

**I/O voltage range is 0~1.8Volt. Otherwise your ODROID will be damaged permanently.**

Refer this link to learn how to use the UART interface.
[[en:u3_ioport_uart|UART interface using the IO-Port #1]]