[en] Measuring system for thermoluminescent dosimetry MR200 was developed at Jozef Stefan Institute in the 80s. The system has been successfully used for almost 20 years in personal and environmental dosimetry, together with the CaF₂:Mn dosimeters, also produced at our institute. New standards in radiation protection dosimetry, as well as recent development of personal computers, were the main reasons to initiate the project of upgrading the system and testing its characteristics for compliance with the IEC international electrotechnical standards. The measuring system is based on the analog part of the TL reader MR200, which remained unchanged. The main elements of the analog part are: the electrically heated oven in nitrogen atmosphere with welded thermocouple, and the optical part with the photo multiplier and the reference light source. The new measuring system is fully PC controlled in the Windows environment. The upgraded MR200 TLD thermoluminescent system preserved all the good measuring properties of the original design. With the new process control many advantages were acquired, making it more user friendly and suitable for routine, as well as research applications. The system complies with the IEC1066 standard for environmental dosimetry. Measuring capabilities can easily be adapted to future demands by means of software changes. One example of future development is adjusting the measuring procedure also for personal dosimetry with use of energy compensated CaF₂:Mn. (author)