Comes after a standard level command and sets all intensity channels not referred to in the command to zero.
5 @ 80 Solo
Sets channel 5 to 80% and all other channels to zero
1 Thru 10 @ 50 Solo
Sets channels 1 thru 10 to 50% and all other channels to zero
Once in Solo mode the command solo by it self will restore the zeroed channels back to their original settings, whilst the channel values set by the solo command will remain as though they had been set without the use of solo.