Telecommunications operators. Men operating radio and telephone equipment, including control panels, headphones, Morse keys, and telephone speakers and receivers. Telegraphy and Morse code was developed in the 1830s and 1840s, telephone technology in the 1870s, and radio technology in the 1890s. This photograph, from the period between 1921 and 1922, is from the National Photo Company Collection, consisting mostly of photographs taken in Washington DC, USA.