Sorry, I dont understand?
When connecting 2 PCs directly without a switch or router, you need a "crossover cable".
The same is true with this device. If you want to connect it directly without a router or switch, a standard ethernet cable will not work. you will need a crossover cable
Technically speaking; it means a special cable that aligns the transmit and receive pins. (So that it's not speaking into the speaker and listening to the microphone.)