L is the type of light source, F is the installation mode, E is the installation height of light bulb, D is the capacity of light bulb, C is the number of light bulbs per lighting device, B is the model or quantity, E is the laying mode and pipe diameter, D is the conductor section, C is the number of wires, and B is the conductor model. D-type suspended ceiling, L-type chain suspension and G-type pipeline suspension.