Comprehensive Product Summary: Moxa NPort Express DE-311 Ethernet to RS232/422/485 1-Port Device Server

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### 1. Product Overview

Product Name: NPort Express DE-311
Model: DE-311
Series: NPort Express Series
Article Number: DE-311
Manufacturer: Moxa Technologies Co., Ltd.
Product Type: Ethernet to RS232/RS422/RS485 1-Port Device Server
Processor: Intel 80186 CPU
Memory: 512 KB RAM
Manufacturer Website: [www.moxa.com](http://www.moxa.com)

The Moxa NPort Express DE-311 is a compact, single-port serial device server designed to connect RS-232, RS-422, or RS-485 serial devices to a 10/100 Mbps Ethernet network. It enables legacy serial equipment to communicate over TCP/IP networks, providing flexible configuration, multiple operation modes, and robust management utilities. The DE-311 is part of Moxa’s NPort Express family, which includes models such as DE-211, DE-311M, and other NPort Server Lite and Pro variants.

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### 2. Key Features

- Ethernet-to-Serial Conversion: Converts RS-232/422/485 serial data to Ethernet TCP/IP packets, enabling remote access and control of serial devices over LAN/WAN.
- Flexible Serial Interface: Supports RS-232, RS-422, and RS-485 communication standards through a DB9 female connector.
- High-Speed Serial Communication: Supports baud rates up to 230.4 Kbps for reliable data transmission.
- Embedded 80186 CPU: Ensures stable, real-time data processing and efficient protocol handling.
- Memory Resources: 512 KB RAM for buffering and firmware operations.
- 10/100 Mbps Ethernet Interface: RJ45 connector supporting auto-negotiation for 10Base-T and 100Base-TX networks.
- Multiple Operation Modes:
- Host Based / Driver Mode (Real COM / Real TTY)
- Pair Connection Mode
- TCP Server / TCP Client
- UDP Server/Client
- Ethernet Modem Mode (unique to NPort Express)
- Cross-Platform Driver Support: Compatible with Windows 95/98/ME/NT/2000/XP (Real COM driver) and Linux (Real TTY driver).
- Advanced Data Packing: Configurable delimiters and force-transmit timers for optimized packetization.
- Access Control: IP-based access management for secure host connections.
- Firmware Upgradeable: Supports remote firmware updates via NPort Management Suite.
- Compact Design: Small form factor for easy integration into industrial and commercial environments.
- Diagnostic and Configuration Tools: Includes NPort Management Suite, Real COM Installer, and Telnet/Serial Console configuration options.

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### 3. Technical Specifications

| Parameter | Specification |
|----------------|-------------------|
| CPU | Intel 80186 |
| Memory | 512 KB RAM |
| Ethernet Interface | 10/100 Mbps, RJ45 connector |
| Serial Interface | RS-232/422/485, DB9 female |
| Supported Baud Rates | Up to 230.4 Kbps |
| Parity / Stop Bits | Supports 2 stop bits, no parity configuration possible |
| Dimensions (W × D × H) | 87 × 100 × 22 mm |
| Weight | Approx. 200 g (typical) |
| Power Supply | External DC input (model dependent) |
| Operating Temperature | 0°C to 55°C (typical) |
| Storage Temperature | -20°C to 85°C |
| Humidity | 5%–95% RH (non-condensing) |
| Enclosure Material | Metal housing for EMI protection |
| Mounting Options | Desktop or wall-mountable |
| Default IP Address | 192.168.127.254 |
| MAC Address | Factory-assigned unique 48-bit address |
| LED Indicators | Power, Ethernet Link/Activity, Serial Tx/Rx (model dependent) |

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### 4. Functionality

The DE-311 functions as a bridge between serial devices and Ethernet networks. It encapsulates serial data into TCP/IP packets, enabling remote monitoring, control, and data acquisition from serial equipment such as PLCs, barcode scanners, CNC machines, and sensors.

Primary Use Cases:
- Industrial automation and SCADA systems
- Remote serial device management
- POS and kiosk systems
- Building automation and access control
- Legacy equipment network integration

Operation Modes:
1. Host Based / Driver Mode:
Creates virtual COM ports on the host PC using Moxa’s Real COM driver (Windows) or Real TTY driver (Linux). Enables transparent communication between serial applications and remote devices.
2. Pair Connection Mode:
Two DE-311 units form a virtual serial cable over Ethernet, extending RS-232/422/485 communication beyond physical distance limits.
3. TCP Server Mode:
The DE-311 listens for incoming TCP connections from clients, suitable for applications where the serial device acts as a server.
4. TCP Client Mode:
The DE-311 initiates a TCP connection to a remote server when serial data is received.
5. UDP Server/Client Mode:
Enables fast, connectionless data transmission and multicast/broadcast communication.
6. Ethernet Modem Mode:
Emulates a dial-up modem for legacy systems (e.g., DOS-based applications) using AT commands and S-registers.

Compatibility:
- Works with standard Ethernet networks (LAN/WAN)
- Compatible with Windows and Linux operating systems
- Supports integration with Moxa’s PComm Lite utilities and third-party serial communication software

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### 5. Components & Accessories

Included Items:
- NPort Express DE-311 device server unit
- Quick installation guide
- Software CD containing NPort Management Suite, drivers, and utilities
- Power adapter (model dependent)
- Mounting hardware (optional)

Connectors:
- Ethernet: RJ45 (10/100Base-T)
- Serial: DB9 female (RS-232/422/485)
- Power: DC input jack

Optional Accessories:
- DIN-rail mounting kit
- Serial cable adapters (DB9 to terminal block)
- External power supply (if not included)
- Cross-over Ethernet cable for direct PC connection

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### 6. Installation & Setup

Requirements:
- Ethernet network (10/100 Mbps)
- Host PC with Windows or Linux OS
- Administrative access for IP configuration

Configuration Methods:
1. NPort Management Suite (Recommended):
Windows-based GUI for device discovery, configuration, firmware upgrade, and monitoring.
2. Telnet Console:
Accessible via IP address (default 192.168.127.254) for text-based configuration.
3. Serial Console:
RS-232 console connection (19200 bps, 8N1) for initial setup when network access is unavailable.
4. ARP Command:
Assigns IP address using MAC-IP mapping from a local host.
5. Real COM Installer:
Maps virtual COM ports on Windows hosts for transparent serial communication.

Mounting Options:
- Desktop placement
- Wall-mounting using brackets
- DIN-rail mounting (optional accessory)

Initial Setup Steps:
1. Connect DE-311 to Ethernet and power source.
2. Assign IP address via NPort Management Suite or ARP.
3. Configure serial parameters (baud rate, parity, stop bits).
4. Select operation mode (Host Based, TCP/UDP, Pair, or Modem).
5. Save and restart the device to apply settings.

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### 7. Performance & Capabilities

- Serial Speed: Up to 230.4 Kbps
- Ethernet Throughput: 10/100 Mbps auto-sensing
- Latency: Low-latency data forwarding suitable for real-time control
- Data Packing: Configurable delimiters and force-transmit timers (1–65535 ms)
- Connection Management:
- TCP alive check (1–99 minutes)
- Inactivity timeout (1–65535 ms)
- Multi-Host Access: Supports multiple host connections with IP-based access control
- Firmware Upgrade: Remote upgrade via Configurator or NPort Management Suite
- Limitations:
- Does not transmit DCD signal in Pair Connection Mode
- Limited to one serial port per device
- Requires static IP for stable operation in DHCP environments

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### 8. Standards & Compliance

- Network Protocols: TCP, UDP, IP, ICMP, ARP, DHCP, BOOTP, Telnet
- Serial Standards: RS-232, RS-422, RS-485 (selectable)
- Operating Systems Supported:
- Windows 95/98/ME/NT/2000/XP (Real COM driver)
- Linux (Real TTY driver)
- Certifications:
- CE (EMC compliance)
- FCC Part 15 Class A
- RoHS (lead-free manufacturing)
- Industry Standards:
- IEEE 802.3 (Ethernet)
- EIA/TIA RS-232/422/485
- ISO/IEC 8802-3 (LAN standards)

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### 9. Additional Information

Warranty:
Standard Moxa limited warranty (typically 3 years) covering manufacturing defects and hardware failures under normal use.

Technical Support:
- Email: support@moxa.com.tw
- Website: [www.moxa.com](http://www.moxa.com)
- Resources: Firmware updates, driver downloads, manuals, and FAQs available online.

Maintenance:
- Periodic firmware updates recommended for security and performance improvements.
- Configuration backups can be exported/imported using NPort Management Suite.
- Device supports remote monitoring via NPort Monitor utility.

Software Utilities:
- NPort Management Suite: Comprehensive configuration and management toolset.
- Configurator: GUI for network and serial parameter setup.
- Real COM Installer: Maps virtual COM ports on Windows hosts.
- NPort Monitor: Monitors port activity and connection status.
- NPort Batch Configurator: Command-line utility for mass configuration (Windows/Linux).
- PComm Lite: Terminal emulator and serial control library for testing and development.

Firmware Configuration Options:
- Server Configuration: IP, Netmask, Gateway, Password
- Serial Settings: Baud rate, data bits, parity, stop bits, flow control
- Access Control: IP-based host permissions
- Operation Modes: Host Based, Pair, TCP/UDP, Ethernet Modem
- Data Packing: Delimiters and force-transmit timers
- AT Commands (Ethernet Modem Mode): Supports standard modem commands (ATA, ATD, ATH, etc.)
- S Registers: Configurable parameters for modem emulation (S0–S12)

Revision History Highlights:
- Edition 3 (Nov 15, 2002): Major revision introducing unified NPort Management Suite and Host Based/Driver Mode.
- Edition 4 (May 12, 2004): Added “Fast Flush” function for improved driver performance and updated Moxa branding.

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### Summary

The Moxa NPort Express DE-311 is a robust, industrial-grade Ethernet-to-serial device server designed to modernize legacy serial communication systems. With its 80186 CPU, 512 KB RAM, and support for multiple serial standards, it provides reliable, high-speed data transmission over Ethernet networks. Its flexible operation modes—ranging from transparent COM port mapping to TCP/UDP socket communication and modem emulation—make it suitable for diverse industrial, commercial, and automation applications.

The DE-311’s comprehensive software suite, including NPort Management Suite and Real COM Installer, simplifies configuration, monitoring, and maintenance. Its compact design, wide compatibility, and proven reliability make it an ideal solution for integrating serial devices into modern IP-based infrastructures.