This paper discusses the relationship between numbering of channel time slot and line time slot by analyzing multiplexing and reflecting of 2 M signal to SDH equipment.

To bring“ wetland” advantage into full play by establishing“ green kidney” which is as important as“ green lung”； set up green“ time channel” by using pluralistic“ cultural meaning” of green space； realize the goal of“ introducing nature into city” with the ecological theory“ climax community”； use the existing laws and regulations on the guaranty of raising the green space to a new stage.

The device can simulate three main transmission impairments in the factual transmission of fiber optic channel,channel delay,channel bit error,channel interruption,provide a convenient instrument to check and measure the protections’performance of relay equipment with the above three impairments.

correspondence between the differential protections at the two ends of the line in the designed message frame format;the communication channel delay in calculating and storing each message frame;judgment of the stability of channel delay according to the criterion inequality.