Comprehensive Product Summary – Rayon F641 8-Port RS232 Connector Box

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### 1. Product Overview

Product Name: F641
Model: F641N (RS232C interface variant)
Series: IOP3927 Intelligent I/O Expansion System
Article Number: F641
Manufacturer: Rayon Technology Co., Ltd.

The Rayon F641 is an 8-port RS232 connector box designed as part of Rayon’s modular Intelligent Input/Output Processor (IOP) system. It provides high-performance serial communication expansion for PC/AT and compatible systems when used with the IOP3927 CPU card. The F641 box integrates eight independent RS232 serial ports, each managed by a FIFO-type 16C554 UART controller, enabling efficient, buffered communication at speeds up to 230.4 kbps. The unit is engineered for industrial and multi-user computing environments requiring reliable, high-density serial connectivity.

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### 2. Key Features

- Eight Independent RS232 Ports:
Each F641 box provides eight fully functional RS232C serial ports, allowing simultaneous communication with multiple external devices such as terminals, modems, or industrial controllers.

- FIFO-Type UART Controller (16C554):
Each port is managed by a 16C554 UART chip featuring built-in FIFO buffers, reducing CPU overhead and improving data throughput and reliability.

- High-Speed Serial Communication:
Supports baud rates from 110 bps up to 230,400 bps, with compatibility mapping for legacy software (high-speed rates mapped to 50–200 bps equivalents).

- Expandable Daisy-Chain Architecture:
Up to eight F641 boxes can be daisy-chained to a single IOP3927 CPU card via DB37 connectors, supporting a total of 64 serial ports per card.

- Hardware and Software Flow Control:
Supports both Xon/Xoff (software) and RTS/CTS (hardware) flow control for flexible communication management.

- System Offload via Intelligent I/O Processor:
When paired with the IOP3927 card, the F641 offloads serial communication tasks from the host CPU, improving overall system performance.

- Flexible Mounting and Expansion:
Modular design allows single or multiple boxes to be mounted using brackets for stable installation in rack or desktop configurations.

- Cross-Platform Driver Support:
Compatible with multiple operating systems including SCO UNIX, Windows NT/2000/XP, and Linux, with dedicated drivers and installation utilities provided by Rayon.

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### 3. Technical Specifications

Interface Type: RS232C
Controller: FIFO-type 16C554 UART (8 channels per box)
Number of Ports: 8 independent serial ports
Connector Type: DB25 male connectors (one per port)
Upstream/Downstream Connectors:
- DB37 female (input from IOP3927 card)
- DB37 male (output to next box in daisy chain)

Pin Assignments (DB25):
- Pin 1 – Frame Ground
- Pin 2 – Transmit Data (TXD)
- Pin 3 – Receive Data (RXD)
- Pin 4 – Request to Send (RTS)
- Pin 5 – Clear to Send (CTS)
- Pin 6 – Data Set Ready (DSR)
- Pin 7 – Signal Ground
- Pin 8 – Data Carrier Detect (DCD)
- Pin 20 – Data Terminal Ready (DTR)

Baud Rate Support:
110, 135, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200, 230400 bps
*(High-speed rates mapped to 50, 75, 150, 200 bps for legacy compatibility.)*

Flow Control: Xon/Xoff or RTS/CTS selectable
Dimensions: 231 mm × 89 mm
Material: Industrial-grade metal enclosure
Weight: Approx. 0.8 kg (typical)
Color/Finish: Rayon standard metallic finish

Environmental Requirements:
- Operating Temperature: 0 °C – 50 °C
- Storage Temperature: –20 °C – 70 °C
- Humidity: 10 % – 90 % non-condensing

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### 4. Functionality

The F641 functions as an external serial communication expansion module for the IOP3927 intelligent I/O processor card. The IOP3927 card, installed in a PC/AT or compatible system, communicates with the F641 via a 37-pin D-type cable. The local RISC processor on the IOP3927 manages data flow between the host CPU and the F641’s UART controllers, significantly reducing main CPU load.

Typical Use Cases:
- Multi-user terminal servers
- Industrial automation systems
- POS (Point-of-Sale) networks
- Data acquisition and control systems
- Communication hubs for modems, printers, or serial sensors

Compatibility:
- Designed for use with IOP3927F CPU card (RS232C type)
- Compatible with P1688U fixed 8-port card (integrated IOP3927 + F641 equivalent)
- Supported operating systems: SCO UNIX, Windows NT 4.0, Windows 2000/XP, Linux

Operation:
Each port operates independently, supporting full-duplex asynchronous communication. The FIFO buffers in the 16C554 controllers ensure smooth data transmission even under high system load. The IOP3927 card’s dual-port RAM architecture allows concurrent access by the local processor and the host CPU, optimizing throughput.

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### 5. Components & Accessories

Included Components:
- F641 8-Port RS232 Connector Box
- DB37 interconnect cable (to IOP3927 card)
- Mounting brackets (for single or multi-box installation)
- Driver and utility diskette (for UNIX, Windows, Linux)
- User manual and installation guide

Optional Accessories:
- Additional F641 boxes (up to 8 per IOP3927 card)
- Daisy-chain interconnect cables (DB37 male-to-female)
- Rack-mount bracket kits for multi-box arrays
- P1688U fixed 8-port card (integrated solution)

Connectors:
- DB37 F (input from IOP3927)
- DB37 M (output to next box)
- 8 × DB25 M (RS232 ports)

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### 6. Installation & Setup

System Requirements:
- IBM PC/AT or compatible system
- Available PCI slot for IOP3927 card
- Supported OS (SCO UNIX 5.0.x, Windows NT/2000/XP, Linux 2.4.x or later)
- Adequate power supply (ensure sufficient wattage for multiple boxes)

Mounting Options:
- Single-box desktop configuration (no bracket required)
- Multi-box daisy-chain configuration (use inter-box brackets)
- Up to eight boxes can be chained and secured on a common base

Connection Procedure:
1. Install the IOP3927F card in a PCI slot.
2. Connect the DB37 cable from the card to the F641’s input connector.
3. For multiple boxes, connect the output DB37 M of one box to the input DB37 F of the next.
4. Secure boxes using provided brackets.
5. Power on the system and verify LED indicators on each box.

Software Setup:
- SCO UNIX: Install driver via `/etc/custom` or `tar` method, rebuild kernel, and reboot.
- Windows NT/2000/XP: Use “Add Adapter” or Plug & Play installation; specify driver path (A:\NT4 or A:\WIN2000).
- Linux: Extract source driver files, compile against kernel source, and install module via `/etc/rayon/Install`.

Verification:
- LEDs on F641 illuminate upon successful driver initialization.
- Device nodes (e.g., `/dev/tty6xx`) or COM ports (e.g., COM3–COM10) become available.

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### 7. Performance & Capabilities

Transmission Speed: Up to 230.4 kbps per port
Port Capacity: 8 ports per box; up to 64 ports per IOP3927 card
System Expansion: Up to 2 IOP3927 cards per system (128 ports total)
Data Handling: FIFO buffering minimizes data loss and CPU load
Flow Control: Hardware (RTS/CTS) and software (Xon/Xoff) supported
Latency: Low-latency communication via local RISC processor management
Reliability: Industrial-grade design ensures stable operation under continuous load

Limitations:
- Requires matching card/box type (IOP3927F ↔ F641/F642 only)
- Dependent on adequate system power supply for multiple boxes
- High-speed modes require compatible driver configuration

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### 8. Standards & Compliance

Electrical Interface:
- RS232C (EIA/TIA-232 standard)

Controller Compliance:
- 16C554 UART compatible with industry-standard 16550 series

System Bus Interface (via IOP3927):
- PCI 2.1 compliant

Regulatory & Safety:
- Designed to meet CE and FCC Class A requirements (industrial/commercial use)
- RoHS-compliant materials (lead-free solder and components)

Software & Driver Standards:
- SCO UNIX 5.0.x kernel integration
- Windows NT 4.0, 2000, XP certified drivers
- Linux 2.4.x + source-level driver compatibility

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### 9. Additional Information

Warranty:
- 1-year limited warranty covering defects in materials and workmanship
- Excludes damage from misuse, unauthorized servicing, or electrical faults

Support & Service:
- Technical support via email: rayon@ms1.hinet.net
- Return Material Authorization (RMA) required for repairs
- Warranty repairs free of charge; out-of-warranty repairs at flat-rate service fee

Maintenance:
- Periodic inspection of connectors and cables recommended
- Keep ventilation unobstructed to prevent overheating
- Firmware and driver updates available from Rayon support

Repair Procedure:
1. Obtain RMA number from Rayon service representative.
2. Provide model, serial number, and fault description.
3. Return product to designated service address.
4. Non-defective units returned under warranty may incur handling/testing fees.

Software Utilities:
- etty: Port test utility for transmit/receive verification
- om: Port monitoring tool for real-time data observation
- setup: Configuration utility for baud rate and port parameters

System Integration Notes:
- Ensure matching card/box types (F-series for RS232, R-series for RISC-based, A-series for SCN2681 controllers).
- Verify BIOS detects IOP3927 card (Vendor ID 0x102F, Device ID 0x000A).
- For Linux, ensure kernel source matches runtime image before compiling driver.

Physical Expansion Example:
- Single-box configuration: standalone operation.
- Two-box configuration: daisy-chain via DB37 cable.
- Eight-box configuration: full 64-port array, secured with inter-box brackets and common base.

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### Summary

The Rayon F641 8-Port RS232 Connector Box is a robust, high-performance serial expansion module engineered for industrial and multi-user computing environments. When paired with the IOP3927F Intelligent I/O Processor Card, it delivers scalable, efficient, and reliable serial communication across up to 64 ports per card. Its modular design, high-speed UART controllers, and comprehensive OS driver support make it an ideal solution for applications requiring dense serial connectivity with minimal CPU overhead.

With its proven architecture, compliance with RS232 standards, and support for UNIX, Windows, and Linux platforms, the F641 remains a versatile and dependable component in Rayon’s intelligent multi-port communication ecosystem.