I tried used Nordic's UART service implementation as a starting point and everything works but I can't figure out where the string "Nordic UART Service" from "nrf connect for Mobile" app comes from. I can see that in https://github.com/nrfconnect/sdk-nrf/blob/main/include/bluetooth/services/nus.h , a service UUID is defined but there does not seem be any "Nordic UART Service" string anywhere. Is it actually a standardized Bluetooth service? If not, how are the UUIDs picked for custom services? Should I just pick a random number here? BT_UUID_128_ENCODE(0x6e400001, 0xb5a3, 0xf393, 0xe0a9, 0xe50e24dcca9e)
Thanks.