Brother HL-1850 Guía Del Usuario

 
The wire which is coloured blue must be connected to the terminal which is 
marked with the letter "N" or coloured black or blue. 
 
The wire which is coloured brown must be connected to the terminal which 
is marked with the letter "L" or coloured red or brown. 
 
The outer sheath of the cord must be secured inside the plug. The coloured 
wires should not hang out of the plug.