Salient Features:

  • Ethernet: RJ45 (100BASE-T / 100 Mbps)
  • Configuration: Web, Telnet
  • RS-232 serial interface: 1x full serial port (9 pins: RxD, TxD, GND, CTS, RTS, DSR, DTR, RI, CD)
  • RS-485 serial interface: Yes, up to 115,200 Bd
  • Support for 9-bit protocols: Yes
  • Box-2-Box mode: Two PortBox2 units can be connected back-to-back over the network.
  • M2M protocols: http, Telnet, TCP Server, TCP Client/Server
  • Support for programmers: HWg-SDK
  • Free HW VSP software: Virtual serial port for Windows (NT service, x64 systems). Supports up to 100 remote serial ports.
  • Advantages: Native support in the “HW VSP” application – the world's most popular virtual serial port for Windows.

Full RS-232 serial port

  • PortBox2 supports full RS-232 serial port in hardware
  • The HW VSP application (Virtual Serial Port) supports full serial ports
  • For third-party SW implementations, RFC2217 can be used
  • PortBox2 also supports 9-bit data transfer over the serial port
  • PortBox2 can be used as an Ethernet com port (remote serial port).

PortBox2: Full RS-232/RS485 serial port to Ethernet

PortBox2 is a RS-232 and RS485 full serial port to Ethernet converter. The remote serial port can be accessed in Windows as a Virtual Serial Port. 
Web-based configuration, full RS-232 (9 wires), 9th bit support (virtual parity).


PortBox2 is a RS-232 and RS485 serial port to Ethernet converter. PortBox2 contains a truly full RS-232 serial port (9 pins). PortBox2 can be connected to a PC over LAN and the serial port can be accessed in Windows as a VSP (Virtual Serial Port), e.g. COM17. HW group offers a free HW VSP Multiportapplication that supports up to 100 remote serial ports on a single PC. It can be used for Windows server applications as well (works as a NT service).


  • Full RS-232 serial port (9 wires)
  • Web-based configuration, free Virtual Serial Port for Windows supports up to 100 ports
  • 9th bit support (virtual parity) for 9-bit protocols

For programmers: Control the product from your own application in minutes. Make your work easier with many examples for various programming languages in the HWg-SDK (Borland C++ Builder, MS Visual C, VB, Delphi, C#, PHP, JAVA).

Extend the serial port over a LAN: Two devices can be connected back-to-back (Box-2-Box mode). In this mode, the RS232/485 serial line is extended (tunneled) over the LAN.




Com port to Ethernet


  • Full remote serial port for connecting any RS-232 device
  • Connecting RS-232/RS485 devices over LAN – barcode / RFID scanners, serial printers, displays, PLC, CNS, various machinery, ...



Com port - Ethernet - Com port


  • The Box-2-Box mode enables connecting two units against each other, 1:1.
  • Extension of RS-232 or RS-485 range over the network



Usage examples

  • Remote control of power and other technology over RS-232 and RS-485
  • Remote control of displays and signal lights
  • RFID card readers, online access control systems
  • Vending machines
  • Security alarms
  • Access control systems
  • Barcode scanners



User software

    • UDP Config – Configuring the product IP address, further configuration over the WEB 
    • Hercules – Configuration (IP address, Telnet configuration) + testing utility for Windows (Serial, UDP and TCP terminal) 
    • HW VSP – Free HW Virtual Serial Port for Windows. 
      PortBox2 is also supported by the VSP Multi version that supports up to 100 virtual serial ports on a single PC.

For programmers



RS-232/485 to Ethernet topology



  • VSP (Virtual Serial Port)
    The HW VSP is installed on the PC to create a virtual serial port (e.g. COM7) in the Windows OS. The full serial port of PortBox2 works like a physical port at the PC. 
  • WEB   [Configuration] 
    Configuration and control of I/O over a WEB interface 
  • TCP/IP Server   [Telnet Client -> Server]
    PortBox2, as a TCP server, listens for incoming TCP connections from a computer (PC or server). When the connection is established, data in the internal buffer are transmitted, and then bidirectional communication can take place, similarly to a common "terminal server" or "device server". Parameters of the remote serial port can be controlled using RFC2217. 

  • TCP/IP Client/Server    [Telnet Server <- Client]
    PortBox2 has received data from the serial port and is attempting to send it to the server. The unit tries to establish a connection to the specified outgoing IP address and port. If it fails in establishing a TCP connection, it waits in the TCP server mode and then tries to establish the connection again. Parameters of the remote serial port can be controlled using RFC2217. 

  • UDP/IP 
    Data are sent as UDP packets, without delivery acknowledgments. 

Variable parity – 9-bit communication

The "Variable Parity" mode is primarily designed for remote control of the 9th parity bit for devices that use 9-bit communication protocols.

The remote 9th "parity" bit can be controlled in 2 ways:

  • Port configuration change using RFC2217 (NVT)
    • Compatible with various virtual serial ports but does not guarantee synchronous parameter change. The timing of NVT command processing is independent of serial port data.
  • "Variable Parity" mode – setting the parity bit for one following character
    • The VIRTUAL PARITY mode must be enabled in the configuration (&V: Variable Parity On).
    • Extension of the RFC2217 standard. Changes the polarity (with respect to the default setting) for a single character that follows the command.
    • The parity of a single character is changed (inverted) if the character is preceded by this 2-byte sequence: 0xFE 0x50.


Pay attention to 0xFF and 0xFE characters

Due to support for "NVT" and "Variable Parity" modes, it is necessary to treat 0xFF and 0xFE characters in the data stream as prefixes for NVT (0xFF) or Variable Parity (0xFE) control. As a result, to send a "0xFF" binary character over the serial interface, it needs to be sent twice over TCP/IP.

Example: 5 bytes are sent over TCP/IP – "0xFF 0xFF 0x41 0xFE 0xFE"; however, PortBox2 only sends 3 characters – "0xFF 0x41 0xFE". If the FF and FE characters are not doubled, they will be processed as control commands depending on the following characters!