Thanks Tweakie, your advice led my to investigation to right track!
Actually, it turned out that I had missed the b0/b1 from the end of the M11/M10 commands.
Valid format is like "M11P1 b1".
Still don't know exactly what the b0 and b1 stand for.
Another thing I noticed was that I was able to get the Ouput1 activated with M11P1 b1 command even without any axis movement.
By giving the command in the Diagnostics view or making and running a G-code file that consists only of M11P1 b1 commands both activated the Output1.
It was against what I expected.
Regards,
Jii