add SERVICE MODE notification

[ballle98]

in stdout-20190815_2101:

21:05:55.762 Debug: PDA Menu Line 0 =
21:05:55.764 Debug: PDA Menu Line 1 =
21:05:55.764 Debug: PDA Menu Line 2 =
21:05:55.765 Debug: PDA Menu Line 3 = SERVICE MODE
21:05:55.766 Debug: PDA Menu Line 4 =
21:05:55.766 Debug: PDA Menu Line 5 = NO OPERATIONS
21:05:55.767 Debug: PDA Menu Line 6 = ALLOWED HERE
21:05:55.768 Debug: PDA Menu Line 7 =
21:05:55.768 Debug: PDA Menu Line 8 =
21:05:55.769 Debug: PDA Menu Line 9 =