You could use the BLE NUS peripheral and central examples to do such a transfer between your devices. The examples will relay anything they receive over UART to their connected peer over BLE, and the peer will output the messages received over BLE out on its UART, and visa versa. Test this according to the example documentation, and let me know if you encounter any issues or questions.
Oh, I did not catch that you wanted to implement a custom service. In this case, please see the Beginner's BLE tutorial series - it starts out with advertising, and covers custom services and characteristics as well in its part II and III.
Oh, I did not catch that you wanted to implement a custom service. In this case, please see the Beginner's BLE tutorial series - it starts out with advertising, and covers custom services and characteristics as well in its part II and III.
