All wireless devices must comply with the local radio regulations which are set by international and national regulatory bodies such as the European Telecommunication Standardization Institute (ETSI) for Europe and the Federal Commission for Communication (FCC) for US. A new firmware module is proposed, that will ensure that devices, in all circumstances will comply with the ETSI regulations for single channel emissions in the 868 MHz ISM band. Namely, assuring compliance with the duty-cycle limit, the maximum TX time and minimum TX-off time limit. Such a solution has not been researched mostly due to the popularity of the virtually worldwide 2.4 GHz ISM band which does not have duty-cycle limitations. The wireless sensor networks (WSN) operating in the 868 MHz band have their own niche applications that benefit from the increased signal range. The development and the acceptance of such applications will benefit from the existence of the proposed module implemented in firmware/software. We propose such a solution and demonstrate its implementation on a custom developed node and protocol. Implementation on top of standardized protocol layers is also analyzed. We also analyze the memory, time and energy overheads caused by including the module in the firmware.