USR-ES1 is an Ethernet module with an SPI interface, operating at a 3.3V TTL level. It requires a stable +3.3V power supply with a current of at least 200mA. The pins are compatible with Wiznet's official WIZ820io module. USR-ES1 integrates Wiznet's W5500 chip, utilizing hardware logic gates to implement the transport and network layers of the TCP/IP protocol stack (including TCP, UDP, ICMP, IPv4, IGMP, PPPoE, etc.). It also incorporates the data link layer, physical layer, and 32KB of on-chip RAM for data transmission buffers. This significantly reduces the workload on the host microcontroller, freeing it from data replication, protocol processing, and interrupt handling, thereby improving system utilization and reliability. Users can treat the W5500 as peripheral RAM for their MCU. The W5500's external interface is a universal 80MHz high-speed SPI, enabling high-speed Ethernet solutions across various platforms. Size: 26x24x17mm Material: PCB Color: As shown Package Contents: 4 x Modules (other products not included).