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

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 UART Service implementation.

The Nordic UART Service is a simple GATT-based service with TX and RX characteristics. Data received from the peer is passed to the application, and the data received from the application of this service is sent to the peer as Handle Value Notifications. The service is used by the application to send and receive ASCII text strings to and from the peer.


Raytac Module MDBT40 series, build by Nordic nRF51822 solution, has been widely applied in IoT based on UART service to help developers obtian a low entry barrier and time to market efficiency .
螢幕快照 2017-04-18 11.07.55

Although UART is a quick and easy access to build up the BLE products, we would like to provide some kind reminding listed in below for all developers.

  1. Packet size: 20 byte
  2. Interval: Suggested set as 50m Sec
  3. For Data <400 byte/sec (baud rate set as 9600), there is no need to support flow control function
  4. For Data>400 byte/sec (baud rate>9600, says as 19200 or 115200), we are strongly suggest to check if MCU support flow control function to avoid data loss.


Raytac Corporation
A BT4.1 & BT4.2 & BT5 module maker based on Nordic nRF51 & nRF52 solution 
(nRF51822 & nRF51422 & nRF52832 & nRF51802 & nRF52840)            Tel: +886.2.3234.0208

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