The distance between two HUB is about 80m, connected with one cascade cross line. The line is corresponding to 1-2, 3-6 line order is correct. Testing by equipment, the cable is normal, but the network is blocked. And the indicator light of tow HUB is not shining.
Make the network cable as the order of orange-white, orange, blue, blue-white, green, brown-white, brown, problem solved.
Because two HUBs are definitely alright, we are sure the problem is on network cable. First we doubt about the network cable head is not good enough. After we make new ones, the problem remains the same. So, the problem must be on the long distance of transmission, the signals’ attenuation is too large, and the cable was not made by standard wire order.