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The DSMs each have a GPS with a pulse-per-second signal. Using NTP reference clock software, each DSM is then a stratum 1 time server. NTP on the DSM adjusts uses the GPS reference clock to adjust the CPU system clock based on the GPS reference clock, and generally reports that the GPS reference clock has less than a 50 micro-second offset from the system clock.
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The above shows that the clock on flux agrees to within a maximum 52 microseconds with each DSM, as indicated by the "Last sample" value in brackets, which is the estimated last calculated offset of the DSM time reference clock (in this case the DSM) from the system time on flux. A positive offset means the reference clock is ahead of the system clock.
The second character, under "S" should be '*' (indicating chrony on flux is sync'd to this server) or '+' (good server). Sometimes I've seen ' You may also see '-' (lately recently on 100m for some reason) indicating chrony does not have a high opinion of its time information, relative to the others.
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