MSM-1250 Modem

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MSM-1250 Modem
MSM-1250.jpg
Frequencies 3 MHz,30 MHz
Frequency Range 3 MHz - 30 MHz
Mode USB
Modulation FSK
ACF
Emission Designator
Bandwidth 2.4 kHz,2.5 kHz
Location Worldwide
Short Description MSM-1250 (Medium Speed Modem) is a 10 FSK-2 OFDM digital data protocol used by the stand-alone modem "SkyFax", used to transmit and receive faxes on HF.
I/Q Raw Recording
Audio Sample

Also known as Racal/Thales Skyfax, Racal/Thales MSM, SKYFAX, Skyfax MSM, JAVELIN MSM-1250, and other variations, MSM-1250 (Medium Speed Modem) is a 10 FSKFrequency-Shift Keying-2 OFDMOrthogonal Frequency-Division Multiplexing (Orthogonal Frequency Division Multiplex) digital data protocol used by the stand-alone modem "SkyFax", used to transmit and receive faxes on HFHigh Frequency (3-30 MHz).

There are 10 parallel FSKFrequency-Shift Keying channels used, each channel spaced 250 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). apart and with 150 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). spacing within the channel. Each channel transmits 125 bpsBits per second (bps), giving a transfer capacity of 1250 bpsBits per second (bps).

This protocol is often seen with MIL 188-141 (ALE). This protocol was developed by Racal (Now Thales Group) and were used in RC5000 series modems marketed by Racal Canada.

Mode Samples[edit]

MSM-1250 MSM-1250 w/with ALEAutomatic Link Establishment: MSM-1250 EOTEnd of Transmission/Idle:
MSM-1250.jpg
MSM-1250 ALE.jpg
MSM-1250 IDLE.jpg

Decoding Software[edit]

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Additional Links[edit]

Additional Images[edit]