The radio NCO and seaman worked with radios, a sonar and intercept device. The on-duty radio seaman used radio to communicate with naval bases and other vessels in the vicinity. During the war, all radio communications were encrypted. 

The only soundproof place on board was the radio cabin where the radio seaman worked with his intercept device. With the intercept device, you would determine the distance of an object based on the direction and volume of the sound. The seaman wore a headset, and by turning a hand wheel, he searched for the direction the sound was coming from. On the display, he could see the degrees, which he then forwarded to the commander. During attacks and when the submarine was targeted by depth charges, the radio seaman played an important role because he was the only person able to hear exactly where the enemy was moving. You can see Vesikko’s intercept device on the right-hand corner of the radio cabin.