Comprehensive Product Summary: MOXA C168P 8-Port RS-232 ISA Card (16550 UART)

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### 1. Product Overview

Product Name: MOXA Smartio C168P
Model: C168P
Series: Smartio/Industio ISA Family
Article Number: C168P
Manufacturer: Moxa Technologies Co., Ltd. (Moxa Inc.)
Product Type: Universal 8-Port Serial Communication Board (ISA Bus)
Release: 7th Edition (May 1999); 8th Edition (June 2008)
Manufacturer Contact:
- Website: [www.moxa.com](http://www.moxa.com)
- Support Email: support@moxa.com.tw
- Technical Support: Available via global regional offices (Americas, Europe, China, Asia-Pacific)

The MOXA C168P is a high-performance, half-size ISA multiport asynchronous serial communication board designed for PC/AT and compatible systems. It provides eight independent RS-232 serial ports, each equipped with a 16550 UART for reliable, buffered communication. The board is part of Moxa’s Smartio family, known for its ASIC-based architecture, software-configurable parameters, and broad operating system support.

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### 2. Key Features

- Eight Independent Serial Ports: Provides 8 asynchronous RS-232 ports for connecting terminals, modems, printers, data acquisition devices, and other serial peripherals.
- Custom ASIC Design: Integrates multiple logic functions into a single ASIC, reducing board size to half-length and improving reliability.
- Software Configuration: No jumpers or DIP switches required; all I/O addresses and IRQs are configured via software utility (Io-irq.exe).
- EEPROM-Based Configuration: On-board EEPROM stores configuration data, ensuring persistent settings across reboots.
- Flexible IRQ and I/O Addressing: Supports IRQ2–5, 7, 10–12, and 15; base I/O address is software-selectable.
- High-Speed UARTs: Each port uses a 16550 UART with 16-byte FIFO buffers, supporting data rates up to 115.2 Kbps.
- IRQ Sharing: Supports one IRQ per card for efficient resource utilization.
- Operating System Compatibility: Drivers available for Windows NT, Windows 95/98, DOS, Linux, and support for UNIX variants (SCO UNIX/XENIX/OpenServer, QNX, FreeBSD).
- API and Development Tools: Bundled with MOXA’s PComm (Windows) and API-232 (DOS) libraries for application development in C, C++, Visual Basic, Delphi, and other languages.
- Compact Half-Size ISA Form Factor: Dimensions 157 mm × 93 mm, suitable for space-constrained industrial PCs.
- Optional Connection Boxes: Supports RS-232, RS-422, and RS-485 via external connection boxes (Opt8A/B/C/D/F/J/Z/S).
- Diagnostic and Monitoring Utilities: Includes tools for port testing, line monitoring, and communication diagnostics.
- Industrial Reliability: Designed for continuous operation in industrial automation, POS, and communication systems.

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### 3. Technical Specifications

| Parameter | Specification |
|----------------|-------------------|
| Bus Interface | ISA (EISA compatible), 16-bit architecture |
| Number of Ports | 8 asynchronous serial ports |
| UART Type | 16550 or compatible (16-byte FIFO) |
| Communication Standard | RS-232 (default), RS-422/485 via optional connection boxes |
| Baud Rate | 50 bps to 115.2 Kbps |
| Data Bits | 5, 6, 7, 8 |
| Stop Bits | 1, 1.5, 2 |
| Parity | None, Even, Odd, Space, Mark |
| I/O Address Range | 0x0000 – 0xFFFF (software selectable) |
| IRQ Options | 2, 3, 4, 5, 7, 10, 11, 12, 15 |
| Interrupt Vector | 0x0000 – 0xFFFF (configurable) |
| Max Throughput | 115.2 Kbps per port |
| Connector Type | DB62 female on board; DB25/DB9 via connection boxes |
| Dimensions | 157 mm (L) × 93 mm (H) |
| Power Requirements | +5V @ 180 mA max, +12V @ 110 mA max, -12V @ 160 mA max |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -20°C to 85°C (typical) |
| Relative Humidity | 5%–95% non-condensing |
| Weight | Approx. 150 g (board only) |
| Material | Multi-layer PCB with gold-plated edge connector |
| Compliance | ISA bus electrical and mechanical standards |

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### 4. Functionality

Operation Principle:
The C168P provides eight independent asynchronous serial channels, each controlled by a 16550 UART. The UARTs handle buffering and interrupt-driven communication, minimizing CPU load. Configuration data (I/O address, IRQ, interrupt vector) is stored in EEPROM and accessed via the Configuration Access Port (CAP).

Configuration Access Port (CAP):
- Default CAP = first port’s base I/O address (e.g., 0x180).
- If jumper JP1 is shorted, CAP is forced to 0xA700 for recovery or quick installation.

Use Cases and Applications:
- Industrial automation and process control systems.
- Multi-user terminal servers and remote access systems.
- POS (Point-of-Sale) and kiosk systems.
- Data acquisition and instrumentation.
- Telecommunication and modem pooling.
- Office automation and serial device networking.

Compatibility:
- Fully compatible with PC/AT ISA bus systems.
- Supports standard COM port addressing and IRQ sharing.
- Works with Moxa connection boxes for RS-232/422/485 interfaces.

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### 5. Components & Accessories

Included Items:
- C168P 8-port serial async board.
- Driver diskettes:
- Windows NT/95/98 driver disk.
- DOS driver disk.
- PComm Lite diskette (Windows communication library).
- Printed User’s Manual.

Optional Connection Boxes (Opt8x Series):
| Model | Interface | Connector Type | Features |
|------------|---------------|--------------------|--------------|
| Opt8A | RS-232 | 8 × DB25 Female | Standard connection box |
| Opt8B | RS-232 | 8 × DB25 Male | Standard connection box |
| Opt8C | RS-232 | 8 × DB25 Male (octopus cable) | 1 m cable |
| Opt8D | RS-232 | 8 × DB9 Male (octopus cable) | 1 m cable |
| Opt8S | RS-232 | 8 × DB25 Female | Surge protection |
| Opt8F | RS-422 | 8 × DB25 Female | 500 VDC isolation protection |
| Opt8Z | RS-422 | 8 × DB25 Female | Non-isolated |
| Opt8J | RS-422/485 | 8 × DB25 Female | DIP-switch selectable RS-422/485 mode |

Cables:
- 1.5 m DB62-to-DB62 cable (for connection boxes).
- Power adapter (110V/220V AC to 5V DC) for RS-422/485 boxes.

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### 6. Installation & Setup

Hardware Installation Options:
1. Quick Installation (Windows NT/95/98, single board):
- Short jumper JP1 (forces CAP = 0xA700).
- Insert board into ISA slot.
- Configure via software; hardware settings auto-updated.
- Cold restart system after configuration.

2. Standard Installation (multiple boards or non-Windows OS):
- Leave JP1 open.
- Use DOS utility Io-irq.exe to configure I/O address, IRQ, and interrupt vector.
- Save configuration to EEPROM.

Default Factory Settings:
- I/O addresses: 0x180–0x1B8 (8 ports, 8-byte spacing).
- IRQ: 10
- INT Vector: 0x1C0
- CAP Jumper JP1: Open

Software Installation:
- Windows NT: Install via Control Panel → Network → Adapters → “MOXA Smartio/Industio Family.”
- Windows 95/98: Run Setup95.exe; configure via “Moxa Smartio/Industio Configuration Panel.”
- DOS: Run DOSINST.EXE, then configure via SETUP.EXE and load driver SER-DRV.EXE.

Driver Configuration:
- Supports up to 4 boards per system.
- COM port numbers configurable (COM1–COM256 for NT, COM1–COM128 for 95/98).
- FIFO trigger levels adjustable (Rx: 1/4/8/14 bytes; Tx: 1–16 bytes).

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### 7. Performance & Capabilities

- Data Rate: 50 bps to 115.2 Kbps (normal speed mode).
- Interrupt Handling: Supports both interrupt vector and polling modes; interrupt vector mode offers higher performance.
- FIFO Buffers: 16-byte transmit and receive buffers per port.
- IRQ Sharing: One IRQ per card; all ports share the same interrupt line.
- Throughput: Optimized for multi-threaded, multi-process environments under Windows NT.
- Reliability: ASIC design minimizes component count and failure points.
- Limitations: Does not support high-speed mode (>115.2 Kbps); limited to ISA bus systems.

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### 8. Standards & Compliance

- Bus Standard: ISA (Industry Standard Architecture), EISA compatible.
- Electrical Standards: RS-232, RS-422, RS-485 (via connection boxes).
- Isolation (Opt8F): 500 VDC isolation protection.
- Regulatory Compliance:
- CE and FCC Class A (typical for Moxa industrial boards).
- Conforms to PC/AT mechanical and electrical specifications.
- Software Standards:
- Win32 COMM API compliant drivers.
- VCOMM-compliant virtual device drivers for Windows 95/98.
- API-232 library for DOS.
- Operating System Support:
- Windows NT 3.x/4.0 (driver included).
- Windows 95/98 (driver included).
- DOS (driver included).
- Linux (available upon request).
- SCO UNIX/OpenServer, SCO XENIX, QNX, FreeBSD (supported by OS).

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### 9. Additional Information

Warranty & Support:
- Standard Moxa limited hardware warranty (typically 3 years).
- Technical support via email, phone, and online resources.
- Driver and manual updates available through Moxa FTP and website.

Maintenance:
- No periodic maintenance required.
- Ensure proper grounding and cable shielding for industrial environments.
- Use surge-protected connection boxes (Opt8S) in high-noise installations.

Software Tools:
- PComm (Windows):
- Serial communication library for Win32 API.
- Includes diagnostic, monitor, and terminal emulator utilities.
- API-232 (DOS):
- Serial programming library supporting C, Pascal, BASIC, Assembly.
- Includes Data Scope and Diagnose utilities.
- RS-485 Programming Support:
- RTS-controlled half-duplex communication.
- Functions: `sio_RTS()`, `sio_write()`, `sio_putb_x()` for automatic RTS toggling.

Troubleshooting Highlights:
- Board Not Detected: Check slot seating, IRQ conflicts, CAP address.
- No Data Transfer: Verify cable wiring and flow control settings.
- CAP Address Unknown: Short JP1 to force CAP = 0xA700, reconfigure via Io-irq.exe.
- IRQ Conflicts: Adjust IRQ in BIOS or via Io-irq utility.

Physical Connector (DB62) Pinout Summary:
- DB62 female connector on bracket connects to external Opt8x boxes.
- Each port includes TxD, RxD, RTS, CTS, DTR, DSR, DCD, and GND signals.
- Pin assignments detailed in Appendix A of the manual.

Environmental & Operational Notes:
- Designed for continuous operation in industrial and commercial environments.
- Recommended ambient temperature: 0–55°C.
- Ensure adequate ventilation in enclosed systems.

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### Summary

The MOXA C168P is a robust, software-configurable, 8-port RS-232 ISA communication board engineered for industrial and commercial serial connectivity. Its ASIC-based design, EEPROM configuration, and comprehensive driver support make it a versatile solution for legacy PC/AT systems requiring multiple serial interfaces. With optional RS-422/485 connectivity, diagnostic utilities, and development libraries, the C168P remains a reliable choice for automation, data acquisition, and communication applications where stability and configurability are paramount.