This article covers MFNDHKAZTH CH9120 WCH シリアルポートサーバーモジュール 10M イーサネット ETH から TTL シリアルポートモジュール.
Overview
The MFNDHKAZTH CH9120 Serial Port Server Module is a compact network conversion module based on WCH's CH9120 chip. It converts TTL-level serial signals to 10 Mbps Ethernet, allowing serial devices to be remotely controlled via LAN. This product is ideal for adding network connectivity to industrial equipment or enabling IoT functionality in embedded systems. It has gained high praise from developers and system integrators for its ability to connect legacy serial devices to TCP/IP networks with minimal effort.
Key Features
Automatic TX/RX Line Switching ― Automatically detects and swaps serial data lines, eliminating wiring confusion. 10 Mbps Ethernet Support ― Adapts to 10BASE-T half/full duplex for stable network communication. IEEE 802.3 Compliant ― Works with standard Ethernet protocols, integrating easily into existing networks. Bidirectional Transparent Transmission ― Passes serial and network data through without modification, so no special drivers or configuration software are needed. * Multiple Operating Modes ― Supports TCP Server, TCP Client, UDP Server, and UDP Client modes, plus DHCP for automatic IP assignment.
Connectivity & Compatibility
The module offers a TTL serial interface (3.3V/5V logic) and can be directly connected to Arduino, Raspberry Pi, various microcontrollers, PLCs, and other serial devices. The Ethernet side uses a standard RJ-45 connector for 10BASE-T hubs or switches. It communicates over TCP/IP and UDP, requiring no special drivers—any OS that supports TCP/UDP can use it (Windows, Linux, macOS, etc.).
Product Info
Based on the CH9120 chip, this module is available through online retailers. Pricing typically falls around 3,000 JPY, offering excellent cost performance. Warranty and accessories vary by seller. It is usually supplied as a bare board; you will need to provide pin headers and cables. Configuration can be done via AT commands or a dedicated utility.
Best Use Cases
Embedded Developers ― Ideal for collecting sensor data or controlling serial devices over a network. One CH9120 module easily adds IoT capability. Industrial System Maintainers ― Perfect for bringing legacy serial equipment (PLCs, measuring instruments, UPS units) under modern network management without costly gateway hardware. * Hobbyists & Electronics Enthusiasts ― A great module for experimenters who want to network serial communication on Raspberry Pi or Arduino prototypes.