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. In this paper 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 868MHz 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 world-wide 2.4 GHz ISM band which at present does not impose duty-cycle limitations. The wireless sensor networks (WSNs) operating in the 868MHz 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 with IEEE 802.15.4 standard is discussed as well. We also analyze the memory, time and energy overheads caused by including the module in the firmware.