Comprehensive Product Summary – Rayon Technology A138 PCIe 8-Port RS422/RS485 Card

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### 1. Product Overview

Product Name: PCIe 8-Port RS422/RS485 Card
Model: A138
Series: APCIe Advanced PCIe Serial Communication Card Series
Article Number: A138
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 Rayon A138 is an industrial-grade PCI Express (PCIe) expansion card designed to provide eight high-performance serial communication ports configurable for RS422 or RS485 operation. It is part of Rayon’s APCIe series of advanced serial interface cards, engineered for robust industrial control, automation, and data acquisition systems requiring reliable multi-port serial connectivity.

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### 2. Key Features

- Eight Independent Serial Ports: Each port can be individually configured for RS422 or RS485 operation via DIP switches.
- High-Performance Controller: Utilizes the Moschip MCS9900 serial communication controller, providing advanced buffering and efficient CPU utilization.
- PCI Express Interface: Fully compliant with PCIe bus architecture, supporting plug-and-play installation and automatic resource allocation by the system BIOS.
- Flexible Configuration: DIP switch selectable interface modes (RS422 or RS485) for each port.
- ADDC (Auto Data Direction Control): Built-in automatic data direction control for RS485 mode, eliminating the need for manual RTS signal management.
- Industrial-Grade Design: Suitable for industrial control environments with wide operating temperature and humidity ranges.
- Comprehensive OS Support: Compatible with Windows 2000, XP, 2003, Vista, Windows 7, and Linux operating systems.
- High-Speed Communication: Supports baud rates from 50 bps up to 115,200 bps (software programmable).
- Memory-Mapped I/O: Efficient memory and I/O mapping assigned automatically by PCI BIOS.
- Expandable System Integration: Supports up to two A138 cards per system, providing up to 16 serial ports.
- Standard Connectors: DB62 female connector on the card, with included expansion cable (DB62 male to 8×DB9 male). Optional DB62 to 8×DB25 male cable available.
- Compact Form Factor: Standard PCIe bracket with dimensions of 135 mm × 105 mm.
- Plug & Play Installation: Fully automatic resource assignment for I/O, memory, and IRQ.
- Industrial Reliability: Designed for continuous operation in demanding environments.

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### 3. Technical Specifications

Controller Chip: Moschip MCS9900
Bus Interface: PCI Express (PCIe)
Number of Ports: 8 independent serial ports
Interface Standards: RS422 / RS485 selectable per port
Baud Rate: 50 to 115,200 bps (software programmable)
Flow Control: Xon/Xoff (software) and RTS/CTS (hardware)
Buffer Size: 128-byte transmit and receive FIFO per port
Connector Type: DB62 female connector on card
Expansion Cable:
- Included: R804 (DB62 male to 8×DB9 male)
- Optional: R801 (DB62 male to 8×DB25 male)
- Other Options: R802 (DB62 male to 8×DB25 female), R803 (DB62 male to DB62 male for RS4232-8 box connection)

Dimensions: 135 mm (L) × 105 mm (W)
Bracket Type: Standard PCIe bracket
Weight: Approx. 120 g (card only)
Material: Multi-layer PCB with industrial-grade components
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)
Maximum Cards per System: 2
Power Requirements: Supplied via PCIe slot (3.3V/12V standard PCIe power)
I/O Mapping: Assigned by PCI BIOS
Memory Mapping: Assigned by PCI BIOS
IRQ Mapping: Up to four IRQs assigned by PCI BIOS

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### 4. Functionality

The A138 card provides eight serial communication channels that can be configured as RS422 or RS485 interfaces. Each port operates independently, allowing mixed configurations within a single card. Configuration is achieved through DIP switches located on the card (SW2 and SW4), where each bit corresponds to a specific port pair (A–D and E–H).

RS422 Mode:
- Full-duplex differential signaling for point-to-point or multi-drop communication.
- Suitable for long-distance, noise-immune data transmission.

RS485 Mode:
- Half-duplex differential signaling for multi-drop networks.
- Auto Data Direction Control (ADDC) automatically manages transmit/receive switching.
- Ideal for multi-node communication in industrial networks.

Use Cases and Applications:
- Industrial automation and control systems
- SCADA and data acquisition networks
- Building management systems
- Machine-to-machine (M2M) communication
- Embedded systems requiring multiple serial interfaces
- Laboratory instrumentation and test equipment
- Serial device servers and converters

Compatibility:
- Fully compatible with PCIe-based PC/AT systems.
- Supports major operating systems: Windows 2000, XP, 2003, Vista, Windows 7, and Linux (kernel 2.6.x and above).
- Linux driver supports up to four cards with device naming convention `/dev/tty2[1–4][a–h]`.

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### 5. Components & Accessories

Included in Package:
- One A138 PCIe 8-port RS422/RS485 interface card
- One R804 expansion cable (DB62 male to 8×DB9 male connectors)
- User manual and driver CD

Optional Accessories:
- R801 Cable: DB62 male to 8×DB25 male connectors
- R802 Cable: DB62 male to 8×DB25 female connectors
- R803 Cable: DB62 male to DB62 male cable for connection with RS4232-8 isolated box
- RS4232-8 Box: External isolation box for converting RS232 to isolated RS422/RS485 interfaces
- TB485 Converter: DB9 to terminal block adapter for RS485 wiring (DATA+, DATA−, GND)

Connector Pin Assignments:
- DB62 female connector pinout supports eight ports with TXD, RXD, RTS, CTS, DSR, DTR, DCD, and GND signals.
- Each port’s pin mapping corresponds to standard RS422/RS485 signal definitions.

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### 6. Installation & Setup

System Requirements:
- Available PCI Express slot (x1 or higher)
- Supported operating system (Windows 2000/XP/2003/Vista/7 or Linux)
- Administrative privileges for driver installation

Installation Procedure:
1. Power off the host system.
2. Insert the A138 card into an available PCIe slot.
3. Secure the card using the bracket screw.
4. Connect the 62-pin expansion cable (R804 or R801) to the card’s DB62 connector.
5. Power on the system.
6. Install the appropriate driver software.

Driver Installation:
- Windows:
- Plug & Play detection automatically identifies the card.
- When prompted, specify the driver path (e.g., `D:\PCIe_Card\APCIe\Win32`).
- The system installs the multifunction controller driver followed by serial port drivers.
- Device Manager will list “PCIe to Multifunction Peripheral Controller” and “PCIe to High Speed Serial Port” entries.
- Linux:
- Copy driver package to `/etc/rayone` directory.
- Run installation script (`./Install.redhat`).
- Select card type (APCIe/MPe9900) and kernel version.
- Rebuild and reboot the system.
- Device nodes `/dev/tty2[1–4][a–h]` will be created for each port.

Configuration:
- DIP switches SW2 and SW4 control interface mode per port:
- OFF: RS485 mode
- ON: RS422 mode
- For RS485 wiring, short DB9 pins 2–3 (DATA+) and 4–6 (DATA−).
- For RS422, use differential pairs TXD+/TXD− and RXD+/RXD−.

Mounting Options:
- Standard PCIe bracket for internal PC installation.
- Optional external connection via RS4232-8 isolation box for extended or isolated applications.

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### 7. Performance & Capabilities

Data Throughput:
- Up to 115.2 kbps per port (software programmable).
- Optional extended mode up to 921.6 kbps depending on driver and system configuration.

Buffering:
- 128-byte transmit and receive FIFO per port minimizes CPU interrupts and enhances throughput.

Interrupt Handling:
- Plug & Play IRQ assignment by PCI BIOS.
- Supports IRQ sharing and memory-mapped I/O for efficient communication.

Capacity:
- Supports up to two A138 cards per system (16 total ports).
- Each port operates independently with full-duplex (RS422) or half-duplex (RS485) communication.

Efficiency:
- Reduced CPU load through buffered communication and intelligent interrupt management.
- Auto Data Direction Control ensures efficient half-duplex operation without software overhead.

Limitations:
- RS485 mode supports half-duplex only.
- Maximum cable length and node count depend on RS422/RS485 electrical characteristics and network topology.
- Not isolated; for galvanic isolation, use external RS4232-8 box or isolated models (A134I, A132I).

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### 8. Standards & Compliance

Bus Standard: PCI Express (PCIe)
Serial Standards: EIA/TIA RS422 and RS485 compliant
Controller Compliance: Moschip MCS9900 compatible
Operating System Support:
- Windows 2000, XP, 2003, Vista, Windows 7
- Linux kernel 2.6.x and above
Plug & Play: Fully compliant with PCI BIOS resource allocation
Environmental Compliance: Designed for industrial temperature and humidity ranges
EMC/EMI: Meets standard PC/AT system electromagnetic compatibility requirements
Industry Standards:
- EIA RS422/RS485 differential signaling
- PCI Express Base Specification
- UART 16950A compatible interface

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### 9. Additional Information

Warranty:
- One-year limited warranty covering defects in materials and workmanship.
- Excludes damage from misuse, unauthorized servicing, or environmental factors.
- Out-of-warranty repairs available at flat-rate service charge.

Support & Maintenance:
- Technical support available via email (rayon@ms1.hinet.net).
- Driver updates and documentation available from Rayon’s website.
- RMA (Return Material Authorization) required for repairs; contact Rayon Service Center for authorization and instructions.

Maintenance Recommendations:
- Avoid inserting or removing the card while the system is powered on.
- Ensure proper grounding and shielding for RS422/RS485 cabling.
- Periodically inspect connectors and cables for wear or oxidation.

Related Products:
- A168: 8-port RS232 PCIe card
- A118: 8-port RS232/RS422/RS485 PCIe card
- A134I: 4-port isolated RS422/RS485 PCIe card
- A124I: 2×RS232 + 2×isolated RS422/RS485 PCIe card
- UTS004: USB to 4-port isolated RS422/RS485 converter
- RS4232-8 Box: External isolation box for 8-port RS422/RS485 systems

Driver and Utility Software:
- Windows driver package (Win32)
- Linux driver package (ver. 9.x.x)
- “RAYMON.EXE” terminal emulation utility for testing COM ports

Repair Procedure:
- Obtain RMA number before returning products.
- Provide model number, serial number, and problem description.
- Products under warranty repaired free of charge if found defective.

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### Summary

The Rayon A138 PCIe 8-Port RS422/RS485 Card is a robust, high-performance serial communication solution tailored for industrial and embedded applications requiring multiple differential serial interfaces. With its Moschip MCS9900 controller, DIP-switch configurability, and comprehensive OS support, it delivers reliable, flexible, and efficient serial connectivity. Its plug-and-play PCIe interface, automatic resource allocation, and ADDC feature simplify integration into modern PC-based control systems. The A138’s modular design, optional accessories, and compatibility with isolation boxes make it a versatile choice for engineers and system integrators seeking scalable, industrial-grade serial communication hardware.