WIZnet's WIZ811MJ works as a breakout board for their W5100 embedded TCP/IP chip.
Also included on the board is an RJ-45 MagJack connector (RJ45 with X’FMR).
It can be used as a component and little effort is required to interface to the W5100.
The WIZ811MJ is an ideal option for users who want a simple solution to adding TCP/IP capability to their project.
 

There is no on-board regulation, so you'll need to supply clean/regulated power sources. All pins of the W5100 are broken out to two pairs of 10-pin, 0.1" pitch headers.
 

For detailed information on implementation of Hardware TCP/IP, refer to the W5100 Datasheet.

 

Features:

• Supports 10/100 Base TX
• Supports half/full duplex operation
• Supports auto-negotiation and auto cross-over detection
• IEEE 802.3/802.3u Compliance
• Operates 3.3V with 5V I/O signal tolerance
• Supports network status indicator LEDs
• Includes Hardware Internet protocols: TCP, IP Ver.4, UDP, ICMP, ARP, PPPoE, IGMP
• Includes Hardware Ethernet protocols: DLC, MAC
• Supports 4 independent connections simultaneously
• Supports MCU bus Interface and SPI Interface
• Supports Direct/Indirect mode bus access
• Supports Socket API for easy application programming
• Interfaces with two 2.54mm pitch 2 x 10 header pin
• Temperature : 0 ~ 70°C (Operation), -40 ~ 85°C (Storage)

Dimensions:

• Board: 55.5x25x23.5 (W x H x D)

Documents:

• Datasheet
• Schematic
• W5100 Datasheet
• WIZnet Product Page (more documents and downloads)