Minecraft wiki entry for Transmission, associated text: Other power components can be used to activate the receiver, but most require additional data to specify their orientation (for example, to specify the direction a lever is attached). Additionally, any non-power component can be used to deactivate the receiver (even air). Avoid using blocks that are transparent or produce light (like redstone torches) as that can increase lag due to block light calculations in up to hundreds of blocks around the receiver.