The aim of the thesis is to describe the principle of REFCON 6 program which is used for monitoring of refrigerated container units via example from practice, and also to describe how the system generally works. How program monitors and diagnose failures and automatically sends notifications if any of the possible failures or alarms on the complete system, either the ship or the terminal is present. The thesis generally describes refrigerated containers, their electrical components and the overall communication system. With the idea conceived in 1956. and the development of the containers themselves as standard multimodal units, container ships allowed new uninterrupted transport chain. With the development of technology and the growing need for transport of temperature-sensitive, frozen or refrigerated cargo, refrigeration technology has been optimized and today brought to the level of almost complete automation. Attention was given to make it easier to understand the complete picture of transport and monitoring of refrigeration units. On the one hand, the human factor in the complete chain from order to delivery of goods is reduced to a minimum, partly for economic reasons and partly for reasons of reliability. By keeping up with technology and by owning new refrigeration units, companies became more competitive and consequently have been making higher revenues, and the customer as a user is getting a transparent insight into all the necessary information regarding cargo which is the most important link in the globalized world.