Description: W5100 is a multi-fuctional network interface chip for MCU, it's integrated with 10/100 Ethernet controller, mainly used in low cost embedded systems with high integration, high stability, and high performance. By using W5100, you can realize Internet connection without an operating system. W5100 is compatible with IEEE802.3 10BASE-T and 802.3u 100BASE-TX. It is also internally integrated with full hardware, and over many years of market validation of the TCP/IP protocol stack. Ethernet medium transport layer (MAC) and physical layer (PHY). You don't have to worry about Ethernet control by using W5100, all you need to do is just simple port (Socket) programming. Multiple interfaces for selection: direct bus, indirect bus and SPI bus. Support hardware TCP/IP protocol stack, support TCP, UDP, ICMP and IGMP, IPv4, ARP,PPPoE. Four separate ports Internal integrated with 16k byte transceiver cache; Instructive output of various information, including RX, TX, Full/Duplex, Colision, Link, Support automatic conversion (DMI/MDIX); 3.3V power supply, IO signal compatible with 5V voltage Built with Ethernet port, and double-row 2*14 2.0mm pins Compatible with Arduino official Ethernet library. Size: approx. 20 x 15mm Color: Red Package Includes: 1 Piece W5100 Ethernet Shield Note: Color maybe slightly different due to different monitor. The above size is measured by hand, please allow slightly difference. Thanks !