1. Product Overview

Product Name: PCIe 4-Port RS232 Card
Model: A104
Series: APCIe Advanced PCIe Serial Communication Card Series
Article Number: A104
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
Websites: [www.rayontech.com](http://www.rayontech.com), [www.computex.com.tw/rayon](http://www.computex.com.tw/rayon)

The Rayon A104 is a four-port PCI Express (PCIe) serial communication card designed for industrial and commercial applications requiring multiple RS232 interfaces. It belongs to Rayon’s APCIe series of advanced serial communication adapters, which include models supporting RS232, RS422, and RS485 standards. The A104 model specifically provides four independent RS232 ports, each managed by a high-performance Moschip MCS9904 controller, ensuring reliable, high-speed serial communication across a wide range of operating systems and environments.

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2. Key Features

- Four Independent RS232 Ports: Each port operates independently, allowing simultaneous communication with multiple serial devices.
- High-Performance Controller: Utilizes the Moschip MCS9904 serial communication controller, compatible with MCS9900 architecture, providing robust data handling and reduced CPU load.
- PCI Express Interface: Fully compliant with PCIe bus architecture, supporting plug-and-play installation and automatic resource allocation by the system BIOS.
- Flexible Baud Rate Configuration: Each port supports software-programmable baud rates from 50 bps up to 115,200 bps, suitable for a wide range of serial communication devices.
- Automatic Resource Mapping: I/O, memory, and IRQ assignments are automatically managed by the PCI BIOS, simplifying installation and configuration.
- DB37 Connector Interface: The card features a DB37 female connector, which connects to an included breakout cable providing four DB9 male connectors for standard RS232 interfacing.
- Cross-Platform Compatibility: Supports Windows 2000, XP, 2003, Vista, Windows 7, and Linux operating systems.
- Industrial-Grade Design: Built for industrial control systems, automation, and data acquisition environments requiring stable and continuous serial communication.
- 128-Byte FIFO Buffers: Each transmit and receive channel includes a 128-byte FIFO buffer, minimizing CPU interrupts and improving overall system performance.
- Flow Control Support: Supports both hardware (RTS/CTS) and software (Xon/Xoff) flow control mechanisms.
- Compact Form Factor: Standard PCIe bracket design with compact dimensions suitable for most PC/AT systems.
- Wide Environmental Tolerance: Designed to operate in environments with temperatures from 0°C to 55°C and humidity up to 95% RH.

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3. Technical Specifications

- Bus Interface: PCI Express (PCIe)
- Controller Chip: Moschip MCS9904 (MCS9900 compatible)
- Number of Ports: 4 independent RS232 ports
- Communication Standard: RS232C
- Baud Rate Range: 50 bps to 115,200 bps (software programmable)
- Flow Control: Xon/Xoff (software), RTS/CTS (hardware)
- FIFO Buffer: 128 bytes transmit and 128 bytes receive per port
- Connector Type: DB37 female on card
- Expansion Cable: DB37 male to 4 × DB9 male (P485 cable, included)
- Optional Cable: DB37 male to 4 × DB25 male (A400 cable, optional)
- Dimensions: 82 mm × 97 mm
- Bracket Type: Standard PCIe bracket
- 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
- Material: Industrial-grade PCB with reinforced connectors
- Weight: Approximately 100–120 g (card only)
- Power Requirements: Supplied via PCIe bus (no external power required)

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4. Functionality

The A104 PCIe card provides four independent RS232 serial communication channels through a single PCI Express slot. Each port is managed by the Moschip MCS9904 controller, which integrates advanced buffering and interrupt management to minimize CPU overhead. The card’s plug-and-play design allows the system BIOS to automatically assign I/O addresses, memory mapping, and IRQs, ensuring seamless integration into modern PC architectures.

Use Cases and Applications:
- Industrial automation and control systems
- Data acquisition and instrumentation
- Point-of-sale (POS) systems
- Serial device networking (modems, sensors, PLCs)
- Laboratory and test equipment communication
- Embedded system development requiring multiple COM ports

Compatibility:
- Fully compatible with PC/AT systems equipped with PCIe slots.
- Supported operating systems include Windows 2000, XP, 2003, Vista, Windows 7, and Linux distributions (RedHat, Fedora, SUSE, Slackware).
- Linux driver support includes kernel versions up to 2.6.x, with installation scripts for major distributions.

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5. Components & Accessories

Included Items:
- A104 PCIe 4-Port RS232 Card
- DB37 male to 4 × DB9 male breakout cable (P485)
- User manual and driver CD (Windows and Linux drivers)

Optional Accessories:
- A400 cable: DB37 male to 4 × DB25 male connectors
- RS4232-4 or RS4232-8 isolated converter boxes for ground isolation and RS422/RS485 conversion
- TB485 converter: DB9 to 3-terminal block adapter for RS485 wiring
- Additional PCIe serial cards in the APCIe series for system expansion

Connectors:
- DB37 Female (on card): Provides connection to breakout cable
- DB9 Male (on cable): Standard RS232 pinout for external devices
- Pin Assignments:
- TXD (Transmit Data)
- RXD (Receive Data)
- RTS (Request to Send)
- CTS (Clear to Send)
- DTR (Data Terminal Ready)
- DSR (Data Set Ready)
- DCD (Data Carrier Detect)
- RI (Ring Indicator)
- GND (Signal Ground)

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6. Installation & Setup

System Requirements:
- Available PCI Express slot (x1 or higher)
- Compatible operating system (Windows 2000/XP/Vista/7 or Linux)
- Administrative privileges for driver installation

Installation Procedure:
1. Power off the computer and disconnect it from the power source.
2. Insert the A104 card into an available PCIe slot.
3. Secure the card using the bracket screw.
4. Connect the DB37 breakout cable to the card’s connector.
5. Power on the system.
6. The BIOS will automatically detect the card and assign I/O, memory, and IRQ resources.
7. Install the appropriate driver from the provided CD or download from Rayon’s website.
8. Verify installation in the operating system’s device manager (Windows) or via `/dev/tty` device nodes (Linux).

Driver Installation:
- Windows:
- Plug-and-play detection via PCI BIOS.
- Install the Moschip-based driver from the CD path (e.g., `G:\PCIe_Card\APCIe\Win32`).
- Device appears as “PCIe to High Speed Serial Port” in Device Manager.
- Linux:
- Copy driver package to `/etc/rayone`.
- Run installation script (`./Install.redhat`).
- Configure card type (APCIe/MPe9900) and kernel version.
- Rebuild and reboot system.
- Ports appear as `/dev/tty21[a–d]` for four-port cards.

Mounting Options:
- Standard PCIe bracket for desktop or industrial PC chassis.
- Compatible with rackmount and embedded systems supporting PCIe expansion.

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7. Performance & Capabilities

- Data Throughput: Up to 115.2 Kbps per port (software programmable)
- Buffering: 128-byte transmit and receive FIFO per channel
- Interrupt Handling: Reduced CPU load through buffered communication and shared IRQ support
- Latency: Low interrupt latency due to PCIe architecture and efficient driver design
- Reliability: Continuous operation under industrial conditions with minimal data loss
- Scalability: Supports up to four A104 cards in a single system, providing up to 16 RS232 ports
- Limitations:
- RS232 only (no RS422/RS485 support on this model)
- Maximum baud rate limited to 115.2 Kbps (higher rates available on other models)
- No galvanic isolation (available in A134I or A124I models)

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8. Standards & Compliance

- Bus Standard: PCI Express (PCIe)
- Serial Communication Standards: EIA/TIA RS232C
- Controller Compliance: Moschip MCS9904 (MCS9900 compatible)
- Plug & Play: Fully compliant with PCI BIOS resource allocation standards
- Operating System Compliance:
- Microsoft Windows 2000, XP, 2003, Vista, Windows 7
- Linux kernel 2.6.x and compatible distributions
- Environmental Compliance: Designed for industrial temperature and humidity ranges
- Electromagnetic Compatibility: Meets standard PC/AT EMI/EMC requirements
- RoHS Compliance: Manufactured with lead-free components (as per Rayon’s industrial product line)

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9. Additional Information

Warranty:
- One-year limited warranty covering defects in materials and workmanship.
- Warranty excludes damage from misuse, unauthorized servicing, or electrical faults.
- Products found defective under warranty will be repaired or replaced at no cost.
- Out-of-warranty repairs are available at a flat-rate service charge.

Support & Maintenance:
- Technical support available via email (rayon@ms1.hinet.net).
- Driver updates and documentation available on Rayon’s website.
- RMA (Return Material Authorization) required for product returns or repairs.
- Customers must provide model number, serial number, and reason for return when requesting RMA.

Maintenance Recommendations:
- Avoid inserting or removing the card while the system is powered on.
- Ensure proper grounding and shielding in industrial environments.
- Periodically check connectors and cables for wear or damage.
- Keep firmware and drivers updated for optimal performance.

Related Models in APCIe Series:
- A102: 2-port RS232 PCIe card
- A132: 2-port RS422/RS485 PCIe card
- A112: 2-port RS232/RS422/RS485 PCIe card
- A114: 4-port RS232/RS422/RS485 PCIe card
- A134: 4-port RS422/RS485 PCIe card
- A134I: 4-port isolated RS422/RS485 PCIe card
- A124I: 2-port RS232 + 2-port isolated RS422/RS485 PCIe card
- A168: 8-port RS232 PCIe card
- A138: 8-port RS422/RS485 PCIe card
- A118: 8-port RS232/RS422/RS485 PCIe card

Driver and Software Updates:
- Windows drivers based on Moschip reference design.
- Linux drivers maintained under `/etc/rayone` directory with support for multiple cards.
- Supports up to four APCIe cards in one system.

Repair Procedure:
- Obtain RMA number before returning any product.
- Include purchase order number and problem description.
- Products under warranty repaired free of charge; non-warranty repairs subject to service fee.

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Summary

The Rayon A104 PCIe 4-Port RS232 Card is a robust, industrial-grade serial communication solution designed for systems requiring multiple RS232 interfaces. With its Moschip MCS9904 controller, automatic PCIe resource management, and cross-platform driver support, the A104 delivers reliable, high-performance serial connectivity for industrial control, automation, and data communication applications. Its plug-and-play design, comprehensive driver support, and compatibility with a wide range of operating systems make it an ideal choice for engineers and system integrators seeking dependable multi-port serial expansion in modern computing environments.