|Enigma ID||M42 (catch-all MFA Moscow designator)||
|Emission mode||USB; MFSK-34, 40 Bd; OFDM-34, DBPSK, 40 Bd; OFDM-34, DQPSK, 40 Bd|
|Known counterpart stations|
Serdolik is a currently semi-retired proprietary full duplex ARQ system used by the Ministry of Foreign Affairs of Russia. From late 1990s until early 2010s, it served as the most common two-way HF mode of that organization. At present, while still being used, it is seen only on a handful of links; most of them have been upgraded to the newer "Perelivt" system.
Its main waveform is 34-tone MFSK at 40 Bd, which offers a gross data rate of 200 bit/s. The modem also contains a 34-carrier OFDM waveform, modulated at 40 Bd using either DBPSK or DQPSK, which offers higher speeds of 1200 bit/s and 2400 bit/s respectively; however, it is rarely used nowadays.
- Serdolik HF communication system - JSC Sozvezdie [accessed May 31st, 2018]