Characteristic explanation：

• The linear wiring structure succinct, is always convenient, is artistic, only needs a data pilot wire and a power transmission line then (for example needs multi-sound sources also to be possible to increase transmission line again), does not need again for each district or a terminal distinction cloth line. 
• May on the original public broadcast system another cloth data pilot wire, then increase this system directly. 
• The system may suppose 128 addressable terminals, may realize to the independent terminal carries on the broadcast willfully, may carry on to all terminals combines the district willfully. 
• Operates simple, direct-viewing.
• Is suitable in units and so on school uses, only needs to combine the district then nimbly to deal with the school temporary or non-periodical adjustments and so on change classroom, grade.