146 | 14 TUNNy: HITlER’S BIGGEST fISH
Teleprinter code produces a rhythmic, warbling sound when transmitted at high speed by
radio. The first interceptors on British soil to listen to the German transmissions described what
they heard as a new kind of music.
The first Tunny radio link, between Berlin and Greece, went into operation on an experi-
mental basis in June 1941. Then, in October 1942, this experimental link closed down, and for
a short time it was thought the Germans had abandoned Tunny. But later that month Tunny
reappeared in a modified form on a link between Berlin and Salonika, and also on a new link
between Königsberg and south Russia: this was the start of a rapid expansion of the Tunny
network. By the time of the Allied invasion of France in 1944, when the Tunny system was at
its peak, twenty-six different links were known to Bletchley Park. The codebreakers gave each
figure 14.2 A war-time memory aide
showing the teleprint code for each of the
keyboard characters used in the Tunny
system. In modern notation the dot would be
written ‘0’ and the cross ‘1’.
The Turing Archive for the History of Computing.