The CH9121 Serial Port to Ethernet Network Module is a compact, rugged bridge that converts UART TTL serial data to Ethernet using TCP/IP. Built for industrial environments, it supports 3.3V and 5V logic levels and is suitable for use with STM32 and 51 (8051) microcontrollers. The module comes in a plastic+metal enclosure and ships as 1 piece per package. Key benefits Enables serial devices to communicate over Ethernet using TCP/IP, enabling remote monitoring, control, and data logging. Broad compatibility with 3.3V and 5V TTL signals, simplifying integration with common microcontrollers such as STM32 and 51. Durable construction with a plastic+metal enclosure designed for reliable operation in industrial settings. Straightforward integration: UART TTL interface to Ethernet bridge reduces custom networking development effort. Key attributes Functionality: Serial Port to Ethernet Network Module with TCP/IP capabilities; TTL transmission. Compatibility: Supports 3.3V and 5V logic levels; suitable for STM32 and 51 (8051) microcontrollers. Size: Compact form factor (exact dimensions not specified in the product title). Material: Plastic + Metal enclosure. Performance: Ethernet connectivity over TCP/IP for serial data transmission; designed for industrial use. Package: 1 piece. Applications and use cases Industrial automation and control: Connect a PLC or sensor network that outputs TTL UART data to an Ethernet network for centralized monitoring, logging, and remote control. Embedded development with STM32 or 51 microcontrollers: Bridge serial data from a microcontroller to a TCP/IP network for remote telemetry, data collection, or device management. Remote diagnostics and maintenance: Stream serial data to a server over Ethernet to enable remote diagnostics, reduce onsite visits, and improve downtime responsiveness. Notes This module is described as a CH9121 Serial Port to Ethernet Network Module, emphasizing TTL transmission, TCP/IP networking, and compatibility with 3.3V/5V systems. The product specifies 1 PCS and a Plastic+Metal enclosure, suitable for integration into a variety of equipment housings and industrial installations.