This is the Russian (Soviet) 12 tone Vocoder system with each channel QPSK modulated at 100 symbols/sec. Each tone has a shift of 200Hz and spans a frequency range of 700Hz to 2900Hz in the Lower Side Band. This system has a distinctive pilot tone (unmodulated) at 300Hz above a kHz point with unconfirmed reports of a pilot tone at 3600Hz and has a maximum capacity of 4800 bits/s. Commonly logged in the UK.