Nordic nRF51822 UART Service Solution (Module: MDBT40)

More information about UART service (AT Command), Pls refer to below link

https://raytac.blog/2018/03/28/nordic-nrf52810-at-command-ble-module-by-raytac-mdbt42q-pat/

UART service, as known as NUS (Nordic UART Service) is the most common and easy way for BLE relating IoT Implement.
Customers who is familiar with Classic Bluetooth are used to call as SPP service.

Nordic nRF52832 UART Service Solution (Module: MDBT42Q)

UART service, as known as NUS (Nordic UART Service) is the most common and easy way for BLE relating IoT Implement.
Customers who is familiar with Classic Bluetooth are used to call as SPP service.
nrf52832-mtu-500bytes-transmission-demo