General
Wavelength	1300 nm
Link budget	12 dB
Dispersion penalty	3 dB
Air humidity	5–95 % (nicht kondensierend)
Overcurrent and reverse polarity protection

The IMC-21A-M-ST media converter from Moxa is an industrial network transceiver that enables reliable conversion of 10/100BaseT(X) Ethernet signals via RJ45 interface into 100BaseFX fiber optic transmission. The device is specifically designed for use in harsh industrial environments and features a robust metal housing with protection rating IP30, which resists mechanical stress and dust ingress in indoor applications. The compact design with DIN rail mounting allows for easy integration into existing enclosures and control systems. The model designation -ST indicates the integrated ST connector for multi-mode fibers, suitable for short to medium transmission distances in industrial settings.

Applications
The IMC-21A-M-ST is suitable for industrial networking applications where a connection between Ethernet-based devices and fiber optic infrastructure is required. Typical use cases include networking of control and automation systems in factories, power supply facilities, or transportation technology, where high electromagnetic interference immunity and reliability are essential. The use of fiber optic cabling offers advantages such as high bandwidth, low signal loss over long distances, and immunity to electromagnetic interference.

Functions and Features in DetailAn integrated Link Fault Pass-Through (LFPT) mechanism enables rapid network fault detection by forwarding fault messages to the connected Ethernet device in case of fiber link failure. This supports network diagnostics and accelerates troubleshooting. The configuration of operating mode, duplex mode, and transmission speed is performed via DIP switches, allowing flexible setup without additional software. The RJ45 interface supports Auto-Negotiation and Auto-MDI/MDI-X, ensuring automatic configuration of the connection.

Technology Explained SimplyOptical transmission operates in multi-mode mode with a wavelength of 1300 nm. The output power (TX) ranges from -10 to -20 dBm, and the receiver sensitivity (RX) ranges from -3 to -32 dBm. The link budget of 12 dB indicates the maximum attenuation the system can compensate for, which is important for planning fiber links. The dispersion penalty of 3 dB accounts for signal distortion due to modal dispersion in multi-mode fibers. Power supply is provided via a terminal block with an input voltage range of 12 to 48 VDC, including integrated overcurrent and reverse polarity protection to prevent device damage.

Compatibility and AccessoriesThe converter is designed for use with multi-mode fiber optic cables connected via an ST connector. It is part of the IMC-21A series and can be combined with other models in the series that support different fiber connectors (SC, ST) or operating modes (single-mode, multi-mode).

Mounting and InstallationMounting is done via a DIN rail, commonly installed in standard enclosures. Installation requires no special tools; cabling is performed using RJ45 connectors and the ST connector. Power supply is connected via the terminal block, requiring a voltage within the range of 12 to 48 VDC. The devices are intended for use in enclosed enclosures, as the IP30 protection rating does not permit direct exposure to weather.

Operational AdvantagesThe IMC-21A-M-ST offers high operational reliability due to its extended operating temperature range of -40 to 75 °C, suitable for use in extreme environments such as outdoor enclosures or climatically demanding production halls. The 5-year manufacturer's warranty underscores the device's reliability. The MTBF (Mean Time Between Failures) is 353,000 hours, indicating a long service life and low failure probability in industrial operation. Certifications according to EN 55032/35, FCC Part 15B, CISPR 32, and IEC 61000-4-2/-3/-4/-5/-6/-8/-11 ensure high EMC and EMS compliance, required for use in critical installations.

Scope of DeliveryThe scope of delivery includes the IMC-21A-M-ST media converter, a quick start guide, and a warranty card.