Milestone Electronics
USB / RS232 / RS422 / RS485 Converter
Bridges USB-based computers with RS232, RS422, and RS485 serial devices, enabling reliable data communication across multiple serial protocols within a single compact unit. Designed for industrial automation, process control, and monitoring networks.
- Supports USB, RS232, RS422, and RS485 communication interfaces
- Creates a virtual COM port on the host system for seamless serial communication
- Enables multi-device RS485 network communication from a USB-equipped computer
- Differential signaling on RS422 for noise immunity over extended cable distances
- Suitable for industrial automation, monitoring, and data acquisition systems
Yes
- In-house manufactured
- 24hr response
- 2,000+ clients served
Product Overview
Multi-protocol serial communication in one device
The USB / RS232 / RS422 / RS485 Converter enables direct communication between USB-equipped computers and devices operating on RS232, RS422, or RS485 serial protocols. By supporting all three serial standards within a single unit, the converter provides a versatile and efficient connectivity solution for industrial and technical environments where legacy serial equipment must interface with modern computing systems.
Once connected to the host computer via USB, the converter creates a virtual serial port within the operating system. This allows existing software applications to communicate with serial devices as if they were attached through a traditional serial port, requiring no changes to the application layer or system configuration.
RS232 support covers direct point-to-point communication with industrial controllers, instruments, and peripheral devices. RS422 extends this capability with differential signaling, providing strong noise immunity and reliable communication across longer cable runs in demanding industrial environments. RS485 support adds multi-device network capability, allowing the converter to serve as the USB interface for distributed automation systems where multiple field devices share the same communication bus.
The converter is designed for use in industrial automation, process control, monitoring networks, data acquisition systems, and building management installations, where serial communication remains a widely adopted standard across connected equipment.
Serial Standard 1
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Key Features
Built for reliable serial communication
One USB connection. Three serial protocols. Designed to connect modern computers with industrial serial equipment across varied communication standards without additional hardware.
USB to RS232 Communication
The converter supports RS232 communication using TX, RX, and GND signals, enabling direct point-to-point data exchange between USB-equipped computers and RS232-compatible industrial controllers, instruments, and peripheral devices.
- TX, RX, and GND signal support
- Compatible with industrial controllers and instruments
- Point-to-point serial communication
RS422 Differential Signaling
RS422 support uses differential signal pairs (+TX, -TX, +RX, -RX) to achieve high noise immunity and stable communication across extended cable lengths, making it suitable for industrial environments where signal integrity is critical.
- Differential +TX, -TX, +RX, -RX signal pairs
- Strong noise immunity in industrial environments
- Reliable point-to-point communication over longer distances
RS485 Multi-Device Network Support
RS485 communication enables multiple devices to share the same bus, allowing computers to interact with numerous field devices within distributed automation systems and industrial monitoring networks through a single USB connection.
- Multi-device communication on a shared bus
- Suitable for distributed automation networks
- Connects USB host to multiple RS485 field devices
Virtual COM Port Creation
Upon USB connection, the converter creates a virtual serial port within the host operating system. This allows existing serial software applications to communicate with connected devices without modification, minimising integration effort and setup time.
- Automatic virtual COM port on USB connection
- Compatible with existing serial software applications
- No changes required to the application layer
Multi-Protocol Support in One Unit
Supporting RS232, RS422, and RS485 within a single device eliminates the need for multiple separate converters when connecting equipment operating on different serial standards within the same communication infrastructure.
- RS232, RS422, and RS485 in one unit
- Reduces hardware count in mixed-protocol installations
- Flexible connectivity for system integrators
Stable Industrial-Grade Data Transmission
The converter ensures stable and reliable data transmission between USB systems and traditional serial devices, making it suitable for continuous operation in industrial environments where communication integrity is essential to system performance.
- Reliable data transmission across protocols
- Designed for industrial and automation environments
- Easy integration without major system changes
Installation
Straightforward setup. No complex configuration.
The USB / RS232 / RS422 / RS485 Converter is designed for simple integration into existing serial communication systems. The installation process involves connecting the appropriate interfaces and allowing the virtual COM port to initialise automatically on the host system.
01
Connect the USB Interface to the Host Computer
Plug the converter into an available USB port on the host computer or control system. The operating system will recognise the device and create a virtual serial port, allowing serial communication software to interact with the converter as a standard COM port.
02
Select and Connect the Serial Protocol
Based on the target device, connect the appropriate serial interface. For RS232 devices, use the TX, RX, and GND connections. For RS422, connect the differential +TX, -TX, +RX, and -RX signal pairs. For RS485 multi-device networks, wire the converter into the shared communication bus.
03
Connect Serial Equipment to the Appropriate Port
Attach the industrial controller, instrument, monitoring device, or RS485 network bus to the corresponding serial port on the converter. Ensure correct polarity and signal wiring for RS422 and RS485 connections to maintain communication stability.
04
Configure Software and Begin Communication
Set the communication parameters (baud rate, data bits, parity, stop bits) in your serial software to match the connected device. Because the converter creates a virtual COM port, existing applications can begin communicating immediately without modification or reconfiguration.
Designed for real-world industrial environments
The USB / RS232 / RS422 / RS485 Converter is deployed across a wide range of industrial and technical settings where USB-equipped computers must communicate with serial devices and networks.
Industrial Automation and Process Control
Connects USB-based supervisory computers to RS232, RS422, or RS485 industrial controllers and PLCs within process control and automation systems, enabling seamless data exchange without replacing existing serial infrastructure.
Serial Communication Interface Conversion
Provides an efficient conversion path from USB to RS232, RS422, or RS485 in systems where modern computers need to communicate with equipment using legacy serial ports, eliminating the need for dedicated serial port hardware on the host machine.
Monitoring and Control Networks
Enables USB-connected computers to interface with RS485 monitoring networks, allowing centralised monitoring and control of multiple field sensors, actuators, and measurement devices connected on the same serial bus.
Acquisition
Supports communication between USB-equipped data acquisition computers and RS232 or RS422 instruments, enabling continuous data collection from industrial sensors, analyzers, and measurement equipment.
Building Management and Facility Automation
Integrates USB-based facility management systems with RS485 building automation networks, supporting communication with HVAC controllers, access control systems, energy meters, and other building infrastructure devices that use serial protocols.
Remote Monitoring and Industrial Communication
Facilitates remote communication between control stations and distributed field equipment over RS485 networks, supporting long-distance serial communication in remote monitoring installations, substations, and industrial communication networks.
USB / RS232 / RS422 / RS485 Converter Specifications
- USB Interface
- RS232 Communication
- RS422 Communication
- RS485 Communication
- General
Frequently asked questions
What is a USB / RS232 / RS422 / RS485 converter used for?
This converter is used to connect modern computers with USB ports to older serial devices. It allows smooth communication between USB systems and equipment that uses RS232, RS422, or RS485 protocols, bridging the gap between modern computing infrastructure and legacy industrial serial hardware.
Can this converter support multiple serial communication types?
Yes, it supports RS232, RS422, and RS485 communication. This makes it a versatile solution for different types of industrial and automation devices, eliminating the need for separate converters when connecting equipment operating on different serial standards within the same system.
Do I need special software to use this converter?
In most cases, the converter creates a virtual COM port on your system once connected via USB. This allows your existing software to communicate with serial devices without major changes. Standard serial communication software and SCADA applications can interact with connected serial devices through this virtual port immediately after connection.
Is this converter suitable for industrial environments?
Yes, it is designed for reliable data transmission and works well in industrial and automation setups. It supports stable communication even in systems with multiple connected devices. RS422’s differential signaling provides additional noise immunity suited to electrically noisy industrial environments, and RS485 support enables connectivity to multi-device field networks commonly used in automation infrastructure.
Where is a USB to RS232 / RS422 / RS485 converter commonly used?
It is commonly used in industrial automation, monitoring systems, data acquisition setups, and building management systems, where serial communication is still widely used. Additional applications include process control systems, instrumentation networks, remote monitoring installations, and distributed field device networks where RS485 multi-drop topologies are common.
What is the difference between RS422 and RS485, and how does the converter handle both?
RS422 is a point-to-point differential signaling protocol that uses separate transmit and receive pairs (+TX, -TX, +RX, -RX), offering high noise immunity across extended cable distances. RS485 uses a shared bus topology, allowing multiple devices to communicate over the same cable, making it the preferred standard for distributed industrial networks. This converter supports both, allowing system integrators to use the appropriate protocol depending on whether they require point-to-point communication or a multi-device shared bus architecture.
Can this converter be used when the host computer does not have a native serial port?
Yes. This is one of the primary use cases for the converter. Modern computers and industrial PCs often omit physical serial ports entirely. By connecting through USB, the converter creates a virtual COM port that allows the host computer to communicate with RS232, RS422, and RS485 devices as if a native serial port were present, making it directly usable with industrial controllers, instruments, and monitoring systems that rely on serial communication standards.
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