Overview:

Mini W5100 Ethernet Network Module Board For Arduino. 

W5100 is a multifunctional Monolithic network interface chip, internal integrate a 10/100 Ethernet controller, it apply to a embedded system which is High-Integrate, high-stability, high-performance but low-cost. By using it, we can complete the internet linking without operating system supporting. W5100 compatible with IEEE802.3 10BASE-T and 802.3u100BASE-TX. W5100 internal integrate TCP/IP,MAC,PHY with full hardware control. We just need to have some simple socket programming rather than considering the control of the Ethernet when we use the W5100.

Feature:

You can choose a variety of interfaces: direct bus, indirect bus and SPI bus.

Support for hardware TCP / IP protocol stack, support TCP, UDP, ICMP, IGMP, IPv4, ARP, PPPoE.

Up to four independent ports.

Internal integration 16 kbyte transceiver cache.

A variety of information outputs, including the RX, TX, Full / Duplex, Colision, Link, Speed.

Support auto-polarity transformation (DMI / MDIX).

3.3V power supply, IO signal compatible with 5V voltage.

It comes with Ethernet port, 2 x 14 2.0 mm double row.

Compatible the official Arduino Ethernet library.

Connecting to your Arduino: 

• V+: This is a 5 Volt pin.
• Ground: There are two. 0 V pin. 
• NSS: This is your 'chip select'. Usually it connects to D10 on the Arduino.
• RST: This is your Reset pin. It should not be connected to your Arduino.
• MO: This is your MOSI it must connect to the MISO pin of your arduino (D12).
• SOK: This is your Clock pin. It should connect to the SCK pon of your Arduino (D13).
• MI: This is your MISO, it must connect to the MOSI of your Arduino (D11).
• POE - & POE+: These are your Power Over Ethernet pins. However, they are not the standard PoE connection, as they derive from pins 7&8 on your RJ45 jack.

Document: 

• Datasheet W5100
• Sch
• Home page W5100