For another device like a smartphone to use any of the Bluetooth "services" which the micro:bit has, it must first be [paired with the micro:bit](/reference/bluetooth/bluetooth-pairing). Once paired, the other device may connect to the micro:bit and exchange data relating to many of the micro:bit's features.
The [Bluetooth UART service](start-uart-service.md) allows another device such as a smartphone to exchange any data it wants to with the micro:bit, in small chunks.
With the Bluetooth UART service running, this block allows a micro:bit to read data which has been received from a Bluetooth connected device, terminating reading and returning the value obtained as soon as a specified delimiter character is encountered. This means that connected devices can send data to the micro:bit and indicate that the complete message has been sent by appending the message with the delimiter character.
```sig
bluetooth.uartRead("");
```
### Example: Starting the Bluetooth UART service and then reading data received from another device which is terminated by ":" character and then displaying it
```blocks
let uart_data: string = "";
let connected = 0;
basic.showString("UART");
bluetooth.startUartService();
bluetooth.onBluetoothConnected(() => {
basic.showString("C");
connected = 1;
while (connected == 1) {
uart_data = bluetooth.uartRead(":");
basic.showString(uart_data);
}
});
bluetooth.onBluetoothDisconnected(() => {
basic.showString("D");
});
```
### Video - UART service guessing game
https://www.youtube.com/watch?v=PgGeWddMAZ0
### Advanced
For more advanced information on the micro:bit Bluetooth UART service including information on using a smartphone, see the [Lancaster University micro:bit runtime technical documentation](http://lancaster-university.github.io/microbit-docs/ble/uart-service/)
### See also
[Bluetooth SIG](https://www.bluetooth.com), [Bluetooth on micro:bit resources](http://bluetooth-mdw.blogspot.co.uk/p/bbc-microbit.html)
