BT900 Series Bluetooth Module
Learn more and compare with similar parts on the family page.

Bluetooth 4.0 dual mode UART module with uFL connector


Antenna Type
U.FL Connector
Chipset (Wireless)
QCA (CSR) 8811
Dimension (Height - mm)
2.5 mm
Dimension (Length - mm)
19 mm
Dimension (Width - mm)
12.5 mm
Frequency Range (Max)
2480 MHz
Frequency Range (Min)
2402 MHz
Logical Interfaces
Serial, GPIO, I2C, SPI, ADC
Operating Systems Supported
Windows, Android and iOS applications UART Firmware Upgrade
Product Type
Embedded Module
System Architecture
Bluetooth 4.0, Dual Mode (Classic + BLE)


Name Part Type Last Updated
EU Certifications - BT900 BT900-SC Certification 12/01/2022
FCC Certifications - BT900 BT900-SC Certification 12/16/2020
ISED (Canada) Certifications - BT900 BT900-SC Certification 12/16/2020
MIC Certifications - BT900 BT900-SC Certification 12/16/2020
Regulatory Information - BT900 BT900-SC Certification 03/17/2023

Buy Now

Distributor Part In Stock Region Buy
Mouser BT900-SC 4396 North America Buy Now
Mouser BT900-SC 4396 North America Buy Now
DigiKey BT900-SC 2432 North America Buy Now
DigiKey BT900-SC 2432 North America Buy Now
Future Electronics BT900-SC 0 North America Buy Now


Where can I download UwTerminal as referenced in the BT900 or BL600 User Guides?

The BT900 and BL600 documents refer to the UwTerminal utility which was the primary utility when these documents were written. This utility is still available in the firmware zip files when they are downloaded from the BT900 Product Page or BL600 Product Page .

However, UwTerminalX is the new improved version of UwTerminal offering additional features not available in predecessor UwTerminal. We recommend working with UwTerminalX as it will support all the features mentioned in the BT900 documentation and offer the additional features, such as access to online Xcompilers.

The latest release of UwTerminalX can be downloaded from our GitHub Repository: UwTerminalX/releases


What could be causing additional power draw when in standby doze state?

There are several functions within an application that can increase current consumption above the measurement indicated in the Datasheet for standby doze, low power mode.

  • Timers
  • GPIOs held in an asserted state
  • LEDs
  • Nested functions - which keep the module from entering the standby doze state
  • UART (when open)


How can I connect a Bluetooth Low Energy Device to a PC?

Bluetooth Low Energy uses Services as opposed to the set of standardized profiles that exists for Classic Bluetooth. While some Bluetooth Low Energy services have been standardized by the Bluetooth SIG, the development of custom services is allowed to meet custom application requirements.
Because Bluetooth Low Energy uses a completely different protocol than Classic Bluetooth and supports custom services, Bluetooth Low Energy devices cannot connect to a computer through the typical Bluetooth configuration of a computer. Therefore, connecting to a PC requires writing and running a Bluetooth Low Energy Central Role/Client application to collect the data sent from the Bluetooth Low Energy peripheral modules. Application development for PCs and Mobile devices is outside the scope of our support. Alternatively, a BL654 USB dongle could be used as a BLE Central Role device, to collect the BLE data and pass it to the PC over a COM Port. However, you would still need an application to view and process the data received over that COM Port.
We generally recommend customers who are new to Bluetooth Low Energy obtain a copy of Getting Started with Bluetooth Low Energy to help them understand the Bluetooth Low Energy protocol and the GATT table. There are also many resources available online which explain this. 

When Bluetooth Low Energy was first introduced and we launched our BL6xx product line (predecessors to the BL65x series) we produced the BL600 and BL620 smartBASIC Application Walkthrough document, which provides an overview of how Bluetooth Low Energy works and how a GATT table is constructed. 

Do you have a smartBASIC example for Android or iOS devices such as smartphones or tablets?

smartBASIC is a programming language developed for our BT900 and BL6xx modules to simplify the code required for programming them. It is not used for developing Android or iOS device applications. BLE applications for Android and iOS devices would need to written in code specific to the Android or iOS platform.

Our, Laird Toolkit Application available for iOS and Android is currently in the process of being updated for Android and iOS to work with newer OS platforms.
Once it is complete we expect to make the source code available, to customers working with our smartBASIC modules, for reference when developing Apps for these platforms.
As of the writing of this FAQ the current version of the Laird Toolkit is still available on the App store for iOS and Google Play for Android, however, it may not work with newer versions of iOS or Android until the updates have been made.
Google Play Store
Apple Store

An alternate resource, the Nordic nRF Toolbox is also available from the iOS App Store and Google Play. The source code for this application is available from Nordic's Website.
nRf Toolbox

Is there protection from Hacking when using smartBASIC modules?

Our Bluetooth 5.0 smartBASIC modules (BL652, BL653, BL654) have the capability of supporting LE Secure Connections Pairing as well as encryption. LE Secure Connection is an enhanced security feature introduced in Bluetooth v4.2. It uses a Federal Information Processing Standards (FIPS) compliant algorithm called Elliptic Curve Diffie Hellman (ECDH) for key generation. 
LE Secure Connections, supports four association models: 

  • Just Works
  • Numeric Comparison (Only for LE Secure Connections)
  • Passkey Entry
  • Out of Band (OOB)

Additional information about LE Secure Connections and the models can be found here:

Our Bluetooth 4.0 smartBASIC modules (BT900 /BL600 /BL620) support Simple Secure Pairing and Encryption 
Additional information about Simple Secure Pairing can be found here:
We recommend reviewing the Pairing, Bonding and Security Manager functions in the BL6xx/BT900 smartBASIC Extensions User Guides. The full security of the Bluetooth/Bluetooth Low Energy connection will depend largely on how the smartBASIC application is written, and what the input/output capabilities are of the devices that are connecting. If either device will not have any input/output capabilities then pairing will have to default to Just Works, which is the least secure pairing method. However there are additional layers of security that can be added to increase protection from hacking when the Just Works pairing model is used.

With Bluetooth Low Energy, to further secure the connection, it is recommended that the metadata for the characteristic attributes are configured for Encryption with man-in-the-middle protection for characteristic value access. This will prevent anyone from accessing data on the module without proper encryption keys. (See BleAttrMetadataEx in the BL6xx/BT900 smartBASIC Extensions User Guides.) Additionally, when using Just Works pairing, or any time additional security is required, we recommend adding a challenge/response question to the application layer, with a timer, which expects the connecting device to respond to the challenge question in a specified period of time after a connection has occurred. If the correct response is not received within that time period the application would force a disconnection. Finally, whisper mode pairing can be used during the pairing process as an additional layer of security. This is accomplished by reducing the Tx power while pairing using BleTxPwrWhilePairing as per the BL6xx/BT900 smartBASIC Extensions User Guide, which will reduce the radius which a hacker would need to breach in order to capture or spoof the encryption procedure.

Online Xcompiler is not accessible is there a way to Xcompile a smartBASIC Application locally when using UwTerminalX?

If you are having issues using the Online Xcompilers it could be related to security settings in your system which may be blocking access to the Online Xcompilers. If you are not able to resolve this it is possible to Xcompile locally by following the steps below:

  1. Disable (uncheck) the Online XCompilers on the Config Tab in UwTerminalX as shown below:
  2. Locate the Xcomp_mmmmm_xxxx_xxxx.exe file in the firmware zip folder (downloaded from module's Product Page) for the version of firmware loaded to the module.
    Note: the Xcomp version MUST match the firmware version loaded to the module or the application will not compile.
    mmmmm = module
    xxxx_xxxx =Xcomp version
  3. Copy or Move the Xcomp_mmmmm_xxxx_xxxx.exe to the same folder the smartBASIC application is stored in as shown below:

You should now be able to Xcompile the application using UwTerminalX by right-clicking in the terminal and selecting one of the Xcompile options :

  • Xcompile
  • Xcompile+Load
  • Xcompile+Load+Run

Select the application from the folder where the Xcomp file is located. UwTerminalX will now look for the local Xcompiler in the application folder.