General
Number of serial ports	2
Data bits	5, 6, 7, 8
Stop bits	1, 1.5, 2
Fibre optic connection	SC
Wavelength multimode	1300 nm
Air humidity	5–95 %
MTBF	1.606.182 h
MTBF (multimode/singlemode)	1.526.091 h

The Moxa NPort 6250-M-SC (EU) is a 2-Port Secure Device Server that connects RS-232/422/485 devices to Ethernet networks. It enables secure and reliable transmission of serial data in industrial environments, particularly in automation, transportation, and utility networks, where stable and protected communication is required. The device features two serial interfaces with DB9 connectors, each individually configurable for RS-232, RS-422, or RS-485. Support for non-standard baud rates allows connection to special devices requiring unusual transmission rates. The serial interface supports baud rates from 50 to 921,600 bps, data bits from 5 to 8, stop bits of 1, 1.5, or 2, and parity options including None, Even, Odd, Space, and Mark. Flow control methods such as RTS/CTS, DTR/DSR, and XON/XOFF are also integrated. For RS-485, pull resistors (1 kΩ / 150 kΩ), a 120 Ω terminator, and automatic direction control (ADDC) are provided.

Applications

The NPort 6250 is designed for critical applications where data transmission availability and security are paramount. It is suitable for integrating legacy devices into modern networks, for example in production facilities, remote monitoring systems, or infrastructure monitoring. Its robust design, support for IPv6, and configuration via HTTPS and SSH also make it appropriate for applications in the public sector or security-critical environments.

Functions and Features in Detail

The device offers intelligent buffering with 64 KB per port, preventing serial data loss during brief network outages. Buffer size can be expanded via an integrated SD card slot, supporting up to 32 GB SD cards (SD 2.0 compatible). Configuration is possible via a web interface (HTTP/HTTPS), Telnet/SSH, a Windows utility application, or a serial console. Support for IPv4 and IPv6 enables use in modern networks. The serial ports can operate in various modes including Real COM, TCP Server, TCP Client, Pair Connection, Terminal, and Reverse Terminal.

Technology Explained Simply

The NPort 6250-M-SC features a network interface with a 10/100BaseT(X) RJ45 port supporting Auto MDI/MDI-X and equipped with integrated magnetic isolation of 1.5 kV. An optional 100BaseFX SC fiber optic connection is available, designed for both multimode and singlemode fibers. With multimode fibers (OM1, 50/125 μm), the maximum range is up to 4 km; with singlemode fibers (G.652), up to 40 km. Transmission occurs at wavelengths of 1300 nm (multimode) and 1310 nm (singlemode). Optical power ranges from -10 to -20 dBm (TX) and -3 to -32 dBm (RX) for multimode, and 0 to -5 dBm (TX) and -3 to -34 dBm (RX) for singlemode. Data transmission security is ensured by SSL/TLS 1.2, SSHv2, and HTTPS, which are considered security-relevant measures according to IEC 62443. Data is transmitted encrypted to prevent unauthorized access.

Compatibility and Accessories

The NPort 6250 is compatible with various operating systems. For Windows, Real COM drivers are available for Windows 95 to 10 (x86/x64) and Windows Server 2008 R2 to 2012 R2 (x64). For Linux, Real TTY drivers are available for kernel versions 2.4.x to 5.x. Additional operating systems such as SCO UNIX, QNX, Solaris, FreeBSD, AIX, HP-UX, and Mac OS X are supported via Fixed TTY drivers. An API is available for Android from version 3.1.x. Devices can be operated in virtual environments such as VMware or Parallels. The network interface supports protocols including TCP, UDP, Telnet, RFC2217, HTTPS, SNMPv1/2c/3, DHCP, DNS, PPPoE, and IPv6.

Mounting and Installation

The device features a compact metal housing designed for wall mounting, desktop placement, or optional DIN rail mounting. Dimensions are 101 x 111 x 29 mm (with mounting ears) or 77 x 111 x 29 mm (without ears). Weight is 240 g. Power supply is 12–48 VDC, with power consumption of 430 mA at 12 VDC. Operating temperature is 0 to 55 °C (standard model), and -40 to 75 °C for -T models. Storage temperature is -40 to 75 °C at 5–95 % humidity (non-condensing).

Operational Advantages

The NPort 6250 offers high availability through buffering, which stores data during network outages and forwards it once the connection is restored. Secure data transmission according to IEC 62443 protects against unauthorized access. Flexible network connectivity via copper or fiber optic enables use in various environments. Support for IPv6 and configuration via HTTPS/SSH enhances security and flexibility. The robust metal housing design and certifications to EN 55032/35, FCC Part 15B, IEC 61000-4-2 to -4-11, UL 60950-1, UL 62368-1, RoHS, CRoHS, WEEE, and NEMA TS2 ensure reliable performance in industrial applications. MTBF is 1,606,182 hours (multimode/singlemode: 1,526,091 hours).