Setting up the Fiscal Data Module with the Flectra POS


The Belgian government requires certain businesses to use a government-certified device called a Fiscal Data Module (also known as a blackbox). This device works together with the POS application and logs certain transactions. On top of that, the used POS application must also be certified by the government and must adhere to strict standards specified by them. Flectra 9 (Professional Edition) is a certified application. More information concerning the Fiscal Data Module can be found on the official website.

Required hardware

  • A government certified Fiscal Data Module per POS, all of them should work, but the Cleancash SC-B is recommended, you will also need:

    • Serial null modem cable per FDM (example)

    • Serial-to-USB adapter per FDM (example)

  • A registered IoT Box per POS configuration


IoT Box

In order to use a Fiscal Data Module, you will need a registered IoT Box. These IoT Boxes are similar to the regular IoT Boxes we sell, but they are registered with the Belgian government. This is required by law. Attempting to use a Fiscal Data Module on a non-registered IoT Box will not work. You can verify that the Fiscal Data Module is recognized by the IoT Box by going to the Hardware status page via the IoT Box homepage.



An Flectra POS app can be given certified POS capabilities by installing the Belgian Registered Cash Register app (technical name: pos_blackbox_be). Because of government restrictions imposed on us, this installation cannot be undone. After this, you will have to ensure that each POS configuration has a unique registered IoT Box associated with it (Point of Sale ‣ Configuration ‣ Point of Sale and ensure Hardware Proxy / IoT Box and the serial number of your IoT Box is set). The first time you open the Point of Sale and attempt to do a transaction, you will be asked to input the PIN that you received with your VAT signing card.


Certification & On-premise

The certification granted by the government is restricted to the use on SaaS instance. The usage of the module from the source or a modified version will not be certified. For on-premise users, we also support the Fiscal Data Module in such installations. The main restriction is that this requires an obfuscated version of the pos_blackbox_be module we will provide on request for Professional customers.


As mentioned before, in order to get certified the POS application must adhere to strict government guidelines. Because of this, a certified Flectra POS has some limitations not present in the non-certified Flectra POS.

  • Refunding is disabled

  • Modifying orderline prices

  • Creating/modifying/deleting POS orders

  • Selling products without a valid tax

  • Multiple Flectra POS configurations per IoT Box are not allowed

  • Using the POS without a connection to the IoT Box (and thus FDM)

  • Blacklisted modules: pos_discount, pos_reprint, pos_loyalty