Date: | 1920s-1930s |
Company: | National Radio Institute |
Location: | Washington, D.C., United States |
For Morse code training. The cylinder is equivalent to a stack of Omnigraph discs. Notches on its surface open and close an electric circuit. The "shoe" can be raised and lowered. The The Morse code key and sounder were added by a previous owner, who also constructed the box.