Cause
Your computer or network card may not support direct connections with an Ethernet cable.
Solution
If communication is not possible with a direct connection to the display unit, use a hub and try connecting again.
Distinguishing between a straight cable and cross cable
Straight cable
When comparing connectors on both ends of the cable, the color-coded signal wires are arranged in the same order.
Cross cable
When comparing connectors on both ends of the cable, the color-coded signal wires are arranged in different orders.