When connecting the AirPort Base Station (Dual Ethernet) to another device over Ethernet, a crossover cable is not required. Both the WAN and LAN Ethernet ports automatically detect the type of connection, and switch the signal configuration as required. The Ethernet jacks do not accept telephone wire (RJ-11). This has been done to prevent confusion from misplugged wiring. The Ethernet jacks will not allow the clip of telephone wire's connector to insert far enough to lock into place.