How was the Tunny cipher machine different from Enigma?

The Tunny cipher machine differed from the Enigma in several key technical and operational ways:

• Automation and Operation: Unlike Enigma, which required three operators (a typist, a transcriber, and a radio operator), Tunny was fully automated. The operator simply typed in plain German, and the machine handled the encryption and transmission directly, meaning neither the sender nor the receiver saw the coded message.1
• Transmission Method: Enigma messages were transmitted in Morse Code. Tunny, however, utilized teleprinter technology and sent messages in binary code, using packets of zeros and ones.12
• Complexity: Tunny was a more sophisticated 12-wheel machine, whereas the standard military Enigma used three or four rotating wheels.12
• Intelligence Value: While Enigma was used for a wide range of communications, Tunny was reserved exclusively for the highest-grade intelligence, specifically messages between the German army’s high command and generals in the field.12

Because of these differences, the anti-Enigma Bombe was ineffective against Tunny, leading to the development of Colossus, the world's first large-scale programmable electronic computer, to break its ciphers.12