> For the complete documentation index, see [llms.txt](https://bananapi.gitbook.io/bpi-m2-ultra-open-source-single-board-computer/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bananapi.gitbook.io/bpi-m2-ultra-open-source-single-board-computer/bpi-m2-berry-hardware/bpi-m2-berry-uart-port.md).

# BPI-M2 Berry UART port

**UART specification:**

The header CON4 is the UART interface. For developers of Banana Pi, this is an easy way to get the UART console output to check the system status and log message.

|          | CON2  Pin Name | Default Function | GPIO |
| -------- | -------------- | ---------------- | ---- |
|          | CON2 P03       | UART0-TXD        |      |
|          | CON2 P02       | UART0-RXD        |      |
| CON2 P01 | GND            |                  |      |