This category is comprised of photographs that document the broadly understood communications – from communication between the fighting units to the activity of the Scout Field Post enabling civilians to contact their loved ones. The photos in this group show the laying of telephone lines by signals units, the so-called "Wires", the repairing of the telephone exchange Jasna Street, radio and telephone operators at work, as well as the maintenance and broadcasts of the famous "Błyskawica" radio station. You can also see mail boxes installed in various locations across the city (there were some 40 of them). Interesting photos by Eugeniusz Lokajski show the so-called "rope mail", i.e. a wicker basket attached to a rope and used for dragging dispatches across Marszałkowska Street.