## 1 Introduction  
Nowadays, the fourth industrial revolution--fourth in the sense of its innovative and qualitative nature--is taking place. On the one hand, the quality of the changes can be seen in the fact that the whole production process is managed and supervised in an integrated way, and is combined, yet flexible. In order to remain competitive in a globalized environment, manufacturing companies need to constantly evolve their production systems and accommodate the changing demands of markets [1]. These, in turn, have a large impact on industry and markets, while affecting the whole life cycle of the product, providing a new means of production and of conducting a business, allowing for an improvement in processes and an increase in the competitiveness of enterprises [2]. Computers, automation and robots existed in previous decades, but the opportunities provided by the Internet revolutionize their use, and the opportunities they provide [3; 4; 5]. The increasingly cheaper solutions allow us to monitor the activities, operation and processes of machines, materials, workers and even products themselves, and to collect, analyze and utilize data in real-time decision making. The fourth industrial revolution is based on data. The way it can be gathered and analyzed, and used to make the right decisions and develop, has become a competitive factor. The source of competitive advantage, therefore, will not only be production on a coordinated or completely new basis (e.g., additive production), but also the embedding of products with digital services (e.g., in the event of a failure, the machine itself indicates which replacement part should be brought in), i.e., how companies filter the relevant information from the generated data in order to support decision-making [3; 4]. In recent decades, manufacturing and production systems have been gradually supplemented by information technology support instruments, because controlling more and more complex technologies, the demands of multi-site production, and supporting logistic processes have become even more complex tasks. The inevitable role of IT (Information Technology) at companies has transformed both working conditions and efficiency, and its importance is unquestionable [6]. Regarding Industry 4.0 readiness, [PERSON] [7] notes that while Hungary is among the most industrialized countries in Europe in terms of manufacturing output versus GDP, the country is below the European average in terms of indicators such as production process sophistication, degree of automation, workforce readiness and innovation intensity. \"Industry 4.0\" provides the relevant answers to the fourth industrial revolution. The main purpose of Industry 4.0 is to achieve improvements in terms of automation and operational efficiency, as well as effectiveness [2]. The emerging Industry 4.0 concept is an umbrella term for a new industrial paradigm which embraces a set of future industrial developments including Cyber-Physical Systems (CPS), the Internet of Things (IoT), the Internet of Services (IoS), Robotics, Big Data, Cloud Manufacturing and Augmented Reality [8]. The adoption of these technologies is essential to the development of more intelligent manufacturing processes, which includes devices, machines, production modules and products that are able to independently exchange information, trigger actions and control each other, thus enabling an intelligent manufacturing environment [9]. The objective of this study is to discover how companies operating in Hungary interpret the phenomenon of Industry 4.0, what kind of Internet of Things (IoT) tools they use to support their processes, and what critical issues they face during adaptation. This paper makes two potential major contributions to the body of knowledge.