Ethernet Shield description:
Based on the WIZ812MJ module by Wiznet, which uses the same W5100 chip as the official Arduino Ethernet shield.
Ethernet Shield specification:
Ethernet Shield pinout:
The RJ45 jack is physically very high due to being mounted on a separate board on top of the shield. Be careful of clearance when trying to stack other shields on top. If the kit is assembled by soldering the WIZ812MJ module directly to the shield it reduces the height of the jack, but prevents the module being removed.
For more detail: Ethernet Shield