The Arduino Ethernet Shield allows an Arduino board to connect to the internet. It is based on the Wiznet W5100 ethernet chip (datasheet). The Wiznet W5100 provides a network (IP) stack capable of both TCP and UDP. It supports up to four simultaneous socket connections. Use the Ethernet library to write sketches that connect to the internet using the shield. The ethernet shield connects to an Arduino board using long wire-wrap headers which extend through the shield. This keeps the pin layout intact and allows another shield to be stacked on top.

Features :

1. Based on the W5100Based on the Wiznet W5100 allows an Arduino board to connect to the internet.
2. Stackable Design, can directly be supported by for Arduino official Ethernet Library.
3. Supports up to four simultaneous socket connections
4. It can be used to store files for serving over the network.
5. Compatible with the for Arduino Duemilanove (168 or 328), Uno as well as Mega (1280/2560).
6. It can be accessed using the Mini SD TF library.
7. The current shield has a Power over Ethernet (PoE) module designed to extract power from a conventional twisted-pair Category 5 Ethernet cable.
8. IEEE802.3af compliant
9. Low output ripple and noise (100mVpp)
10. Overload and short-circuit protection
11. 1500V isolation (input to output)