Technical informations - Systems

MERLIN/ALIS-2/RS-ARQ /RS ARQ 240
This is the 240 bd 8 tone burst ARQ mode used in the Rohde & Schwarz MERLIN modem. When the system is found in the 7 tone mode it is in ISS mode, the IRS mode uses an 8 tone signal. Both will be measured as 240 bd (720 bits/sec) with tones shifted by 240Hz. Character set can be ITA2 or ASCII with 8 bit ASCII being the most common.
Turkish, German and Italian Diplo stations are the most commonly found users.
The Italian Diplo stations seem to favor the 5 bit (ITA2) mode. Turkish Diplo stations have been found using the 8 bit mode for all traffic.
Monitoring tip: Its been discovered that all 8 tone channels have ALIS (228.7bd) 2kHz below. So if you hear an ALIS procedure in progress on a frequency it's worth waiting to see if 8 tone traffic appears 2kHz higher soon after.
 

 RS ARQ II  RS ARQ II