Features

Standard RPi Pico header, fits Raspberry Pi Pico series
Onboard Ethernet to UART transparent transceiver, 2-CH UART, standalone transparent transmission for each channel
Onboard jumpers for pin configurations
Embedded Ethernet MAC and PHY layers
Bi-direction transparent data transmission between UART and Ethernet
10/100M, full-duplex/half-duplex auto-negotiation Ethernet interface, 802.3-compliant
Auto-MDI/MDIX, detect and switch cable type automatically
Supports DHCP auto-obtained IP and DNS domain access
Network parameter configuration like chip operating mode, port, IP, via host computer software or UART command
Four operating modes: TCP CLIENT, TCP SERVER, UDP CLIENT, UDP SERVER
Full-duplex or half-duplex UART communication, supports RS485 RX/TX auto switch (external RS485 controller required)
Supports virtual serial port software (provided)
KEEPALIVE mechanism support
Comes with development resources and manual (examples for Pico/Raspberry Pi/Ardui/STM32)

Part List

1. Pico-ETH-CH9121 x

Resources available: http://www.waveshare.com/wiki/Pico-ETH-CH9121