Comments:
Type of call signs: figure-letter-letter, e.g. 6DG [6ДГ], 4ChN [4ШН].
Operating signals and procedure signs (corresponding to the international Q-code) are formed like the ciphers for
letters and figures. All such signals are marked with a question mark in the chart above, together with a
figure, indicating in which key (RA 1, RA 2, or RA 3) the signal was given when intercepted.
When deciphering, great care must be taken to avoid the many errors made both by the sender and the interceptor. The
most common errors encountered are mix-ups of 0, 1 and 9; this has the effect, that п and р
very often is represented by 9r and 9p in RA 1.
Identification of the figures are not completely certain. There is much to suggest, that the figures have multiple
representations [in the chart]. Cells, which probably hold a figure, are marked with the letter S in the above chart.
Key RA 1 is by far the most common. There are an additional 4 or 5 keys which have seen use, and one is partially broken.
That key (RA 4) seems to have multiple letter coordinates, and the chart seems to be different from the one above. The other
keys have not been broken so far, due to lack of intercepts.
Most of the messages enciphered by the above system, all start with the letters нач [short for начальник] (leader)
followed by a surname or an occupation. The signature is in most cases a name or зу (земелное управление) =
country administration.
The content is usually of political, economical, or administrative nature, and hence of little military interest. On
occasion, messages dealing with troop movements, crossing of rivers etc. have been intercepted, which may indicate that
this cipher system is used by some of the army stations, or that the Cheka stations relay army traffic.