VT-FB820 Key Advantages
20km Extension: Long-distance telemetry via Single-Mode SC fiber.
Zero EMI: Absolute signal isolation for heavy industrial environments.
Universal Serial: Auto-sensing RS232, RS485, and RS422.
Plug & Play: Zero software configuration required. Just connect and power on.
Note:VT-FB820 comes in two sub-models: VT-FB820-A (A-end unit) and VT-FB820-B (B-end unit). These two models must be used in pairs. That is, A-end unit connects to B-end unit; B-end unit connects to A-end unit. Units with the same ports cannot be connected together.
Support Rail mount and Wall mount installation
| Category | Parameter | Specification |
| Appearance | Interface | RS422/485: Terminal Block; RS232: DB9; Fiber: SC Interface |
| Power Supply | 5.5mm standard socket / terminal block (Inside positive, outside negative) | |
| Dimensions | 9.4cm × 6.5cm × 2.5cm (L x W x H) | |
| Interfaces | Serial Port | 1x RS232/485/422 (RXD, TXD, GND, CTS, RTS) |
| Optical Fiber | Single-mode Single-fiber, Bi-directional | |
| Serial Data | Baud Rate | Up to 115200 bps |
| Check Bit | None, Odd, Even, Mark, Space | |
| Data Size | 5～9 bits | |
| Flow Control | None | |
| Fiber Optics | Wavelength | VT-FB820-A (A-end): TX 1310nm / RX 1550nm VT-FB820-B (B-end): TX 1550nm / RX 1310nm |
| Max Distance | 20 Km | |
| Fiber Interface | SC | |
| Power | Input Voltage | 9～24V DC (357mA @ 9V) |
| Environment | Operating Temp | -40℃ to 85℃ |
| Storage Temp | -45℃ to 105℃ |
The Valtoris VT-FB820 is an industrial-grade Serial-to-Fiber media converter designed to seamlessly bridge RS232, RS485, or RS422 signals over a single-mode fiber optic cable. By utilizing paired A-end and B-end units with standard SC interfaces, it extends your serial network up to 20 kilometers while completely isolating your equipment from severe electromagnetic interference (EMI).
It has real plug and play deployment. No software configuration is required. Plug in your serial cables and fiber line, turn it on and your data is flowing right away. The fiber linking and bidirectional data transmission have built-in LED indicators for easy on-site troubleshooting.
A: No. The VT-FB820 is strictly designed for Single-Mode (SM) fiber optics. Attempting to push a single-mode laser signal through a multi-mode core will cause severe modal dispersion and link failure, even over very short distances. Always ensure your site’s optical distribution frame is patched with Single-Mode SC cables.
A: No. The converter has a fully auto-sensing transparent bridge. It has automatic baud rate detection up to 115200 bps and accepts all parity/stop-bit formats without DIP switches or web interfaces. Your serial payloads (e.g. Modbus RTU) are sent on exactly as received.
A: We wouldn’t suggest that. The unit utilizes standard WDM wavelengths (1310nm/1550nm) but the proprietary serial-to-optical modulation timings vary amongst manufacturers. Always use the VT-FB820 as matched A-end and B-end pair to ensure zero packet loss and no ground loop crashes.
A: No, this is a purely physical Layer 1 media converter (Serial in, Serial out over long distances). It does not perform protocol translation. If you need to convert legacy RS485 data into TCP/IP network packets over fiber, you need our [Valtoris VT-FB810 Fiber Serial Device Server]
[RS232 to Ethernet Cable Pinout: Two Common Wiring Diagrams] — Before your data travels across the optical fiber, you must physically connect your PLC to the VT-FB820’s serial port. Use this guide to ensure your RS232 DB9 (TX/RX) crossover wiring is correct at the terminal end.
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