1. Product Overview

Product Name: USB 2.0 to 2×RS232 and Isolated 1×RS232 + 1×RS485/422 Converter
Model: UTS211
Series: UTS400 Series – USB to Serial Port Converter
Article Number: UTS211
Manufacturer: Rayon Technology Co., Ltd.
Manufacturer Address: 2F, No. 177, Chung Shan 2 Rd., Lu Chou City, Taipei Hsien, Taiwan
Contact:
- Tel: +886-2-82858362
- Fax: +886-2-82857065
- Email: rayon@ms1.hinet.net
- Web: [www.rayontech.com](http://www.rayontech.com)

The UTS211 is a high-performance external USB-to-serial converter module designed to provide four independent serial communication ports through a single USB 2.0 interface. It integrates two standard RS232 ports, one isolated RS232 port, and one isolated RS422/RS485 port, all housed in a durable metal enclosure. The device is part of Rayon’s UTS400 series, which is engineered for industrial, laboratory, and commercial applications requiring reliable serial communication over USB connections.

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2. Key Features

- Four Serial Ports in One Module: Provides 2×RS232, 1×Isolated RS232, and 1×Isolated RS422/RS485 interfaces.
- USB 2.0 Compliance: Fully compatible with USB 2.0 specifications, ensuring high-speed data transfer and backward compatibility with USB 1.1.
- MOSCHIP MCS7840 Controller: Utilizes the MCS7840 USB-to-serial bridge chip, offering stable performance and advanced serial communication features.
- 512-Byte FIFO per Port: Each serial channel includes a 512-byte FIFO buffer for efficient data handling and reduced latency.
- LED Indicators per Channel: Individual TX/RX activity LEDs for each port (ATRD, BTRD, CTRD, DTRD) plus a power indicator (PWR).
- Bus-Powered Operation: Draws power directly from the USB bus (5VDC, 400mA), eliminating the need for an external power supply.
- Optional Self-Powered Version: The UTS400S variant supports external 5VDC adapter input for self-powered operation.
- Galvanic Isolation: Isolated RS232 and RS422/RS485 ports provide electrical isolation for enhanced safety and noise immunity.
- Flexible Interface Configuration: RS422 or RS485 mode selectable via DIP switch; supports Auto Data Direction Control in RS485 mode.
- Compact Metal Enclosure: Rugged 90×150×27 mm metal housing ensures durability and EMI shielding.
- Hot-Pluggable USB Interface: Supports plug-and-play installation without system reboot.
- iSerial Feature Support: When programmed with a unique EEPROM serial number, the MCS7840 retains consistent COM port assignments across USB ports.

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3. Technical Specifications

Physical Characteristics:
- Dimensions: 90 mm (W) × 150 mm (L) × 27 mm (H)
- Enclosure Material: Metal (provides mechanical protection and EMI shielding)
- Weight: Not specified (approx. < 500 g typical for metal-cased converters)

Electrical Characteristics:
- Power Supply: USB bus-powered (5VDC ±5%)
- Current Consumption: 400 mA @ 5VDC
- Optional Power Mode: Self-powered version (UTS400S) supports external 5VDC adapter

USB Interface:
- Connector Type: USB Type-B female
- Standard: USB 2.0 (Full-Speed and High-Speed compatible)
- Controller IC: MOSCHIP MCS7840
- FIFO Buffer: 512 bytes per serial port

Serial Port Interface:
- Connector Type: DB9 male connectors (4 total)
- Port Configuration:
- Port A: RS232
- Port B: RS232
- Port C: Isolated RS232
- Port D: Isolated RS422/RS485 (selectable)
- Signal Pins (RS422/RS485): TX+, TX−, RX+, RX−, Isolated GND
- RS485 Mode: Auto Data Direction Control supported
- RS422/RS485 Selection: Configurable via DIP switch
- RS485 Wiring: TX+ and RX+ shorted as DATA+; TX− and RX− shorted as DATA−

Environmental Conditions:
- Operating Temperature: 0°C to 55°C
- Storage Temperature: 0°C to 65°C
- Operating Humidity: 10% to 95% RH (non-condensing)
- Storage Humidity: 5% to 95% RH (non-condensing)

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4. Functionality

The UTS211 functions as a USB-to-multi-serial converter, enabling a host computer to communicate with multiple serial devices simultaneously through a single USB connection. It is ideal for applications where legacy serial interfaces must be integrated into modern USB-based systems.

Operation Principle:
Upon connection to a USB port, the UTS211 enumerates as four independent COM ports on the host system. Each port operates independently, allowing simultaneous data transmission and reception. The MCS7840 controller manages USB communication and serial data conversion, while the onboard isolation circuitry protects connected devices from ground loops and electrical surges.

Use Cases and Applications:
- Industrial automation and control systems
- Data acquisition and instrumentation
- Point-of-Sale (POS) systems
- Laboratory equipment interfacing
- Serial device monitoring and logging
- Communication with PLCs, sensors, and modems
- Integration of legacy RS232/RS485 devices into modern PCs

Compatibility:
- Compatible with Windows, Linux, and other operating systems supporting USB CDC or vendor-specific drivers for MCS7840.
- Backward compatible with USB 1.1 ports.
- Supports hot-plugging and dynamic COM port assignment.

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5. Components & Accessories

Included Items:
- UTS211 converter unit (metal enclosure)
- USB cable (Model U101): 6-foot USB Type-A to Type-B cable
- User documentation (may include driver CD or download link)

Optional Accessories:
- External 5VDC power adapter (for self-powered operation, UTS400S variant)
- Mounting brackets or DIN-rail adapters (optional, depending on installation environment)

Connectors:
- USB Port: Type-B female connector
- Serial Ports: Four DB9 male connectors
- LED Indicators:
- PWR: Power ON indicator
- ATRD: Port A TX/RX activity
- BTRD: Port B TX/RX activity
- CTRD: Port C TX/RX activity
- DTRD: Port D TX/RX activity

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6. Installation & Setup

Requirements:
- Host computer with available USB 2.0 port
- Supported operating system with appropriate drivers (MCS7840 driver package)
- USB cable (included)

Installation Steps:
1. Connect the UTS211 to the host computer using the supplied USB cable.
2. The operating system detects the device and prompts for driver installation.
3. Install the MCS7840 driver (available from Rayon or MOSCHIP).
4. Once installed, four COM ports appear in the system’s device manager.
5. Connect serial devices to the DB9 ports as required.
6. For RS422/RS485 configuration, set the DIP switch to the desired mode before operation.

Mounting Options:
- Desktop placement (standard)
- Optional wall or DIN-rail mounting (depending on accessories)

Configuration:
- RS422/RS485 selection via DIP switch
- RS485 Auto Data Direction Control enabled by default
- iSerial feature can be enabled by programming a unique serial number into the EEPROM (ensures consistent COM port numbering across USB ports)

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7. Performance & Capabilities

Data Throughput:
- High-speed USB 2.0 interface ensures efficient data transfer between host and serial devices.
- Each serial port supports independent full-duplex communication.

Buffering:
- 512-byte FIFO per port minimizes data loss and improves throughput during high-speed communication.

Isolation Performance:
- Isolated RS232 and RS422/RS485 ports provide galvanic isolation, protecting connected equipment from voltage spikes and ground potential differences.

RS485 Auto Direction Control:
- Automatically manages transmit/receive switching, simplifying half-duplex communication setup.

Speed and Capacity:
- Supports standard baud rates up to 921.6 kbps (typical for MCS7840-based converters).
- Capable of handling multiple simultaneous serial sessions without performance degradation.

Limitations:
- Total current draw limited to 400 mA from USB bus; high-power peripherals may require self-powered version.
- DIP switch configuration requires access to internal or side panel (depending on model).

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8. Standards & Compliance

USB Compliance:
- Conforms to USB 2.0 specification (Full-Speed and High-Speed modes).

Serial Communication Standards:
- RS232 (EIA/TIA-232)
- RS422 (EIA/TIA-422)
- RS485 (EIA/TIA-485)

Electrical Isolation:
- Isolated ports meet industrial isolation standards for signal integrity and safety.

Regulatory Compliance:
- CE and FCC compliance (typical for Rayon industrial communication products).
- RoHS compliant (lead-free manufacturing).

Industry Standards:
- Compatible with standard serial communication protocols and signaling levels.
- Supports Auto Data Direction Control in RS485 mode per industry convention.

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9. Additional Information

Warranty:
- Standard manufacturer warranty (typically 1 year, depending on region and distributor).

Technical Support:
- Provided by Rayon Technology Co., Ltd. via email and phone.
- Driver updates and documentation available on the official website.

Maintenance:
- No periodic maintenance required.
- Keep connectors clean and ensure proper cable strain relief.
- Avoid exposure to excessive heat, moisture, or vibration.

Firmware & Driver Updates:
- MCS7840 driver updates available from MOSCHIP or Rayon’s support page.
- EEPROM can be programmed with unique serial numbers to enable iSerial functionality.

iSerial Feature (MCS7840/MCS7820):
- When a unique serial number is written into the EEPROM, the operating system assigns consistent COM port numbers regardless of which USB port the device is connected to.
- This feature simplifies system integration and prevents reconfiguration when moving between USB ports.

Model Comparison (UTS400 Series):
| Model | RS232 | Isolated RS232 | Isolated RS422/485 | Total Ports |
|--------|--------|----------------|--------------------|--------------|
| UTS400 | 4 | 0 | 0 | 4 |
| UTS211 | 2 | 1 | 1 | 4 |
| UTS022 | 0 | 2 | 2 | 4 |
| UTS013 | 0 | 1 | 3 | 4 |
| UTS031 | 0 | 3 | 1 | 4 |
| UTS004 | 0 | 0 | 4 | 4 |

The UTS211 occupies a balanced position in the series, offering both standard and isolated ports for mixed-environment applications requiring flexibility and electrical protection.

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Summary

The Rayon UTS211 USB 2.0 to 2×RS232 + Isolated 1×RS232 + Isolated 1×RS422/RS485 Converter is a robust, industrial-grade communication interface designed to bridge modern USB systems with legacy serial equipment. Featuring four independent serial channels, galvanic isolation, and a high-performance MCS7840 controller, it ensures reliable data transmission in demanding environments. Its compact metal housing, LED indicators, and plug-and-play USB interface make it suitable for automation, instrumentation, and data communication applications where stability, safety, and flexibility are paramount.

With its combination of isolated and non-isolated ports, the UTS211 provides a versatile solution for engineers and system integrators seeking to consolidate multiple serial interfaces into a single, efficient USB-connected module.