USB TO RS485 (C)
The USB TO RS485 (C) is an industrial‑grade, isolated USB‑to‑RS485 bidirectional converter based on the FT232RNL chip. It converts a host USB interface into an RS485 differential bus interface, suitable for industrial control, device debugging, Modbus device communication, long‑distance serial communication, and similar applications.
The module features an isolated transceiver, TVS, ESD protection, a resettable fuse, and protection diodes, enhancing noise immunity in harsh industrial environments and reducing the impact of surges, ESD, ground potential differences, and incorrect wiring on the host and bus devices.
| SKU | Product |
|---|---|
| 34620 | USB TO RS485 (C) |
Features
- USB‑to‑RS485 communication with hardware‑automatic data direction control
- FT232RNL chip for good compatibility, stable, and reliable communication
- Onboard isolated transceiver integrating electrical isolation and ESD protection
- RS485 interface with surge, lightning, and ESD protection
- Onboard resettable fuse and protection diodes for enhanced overcurrent, overvoltage, and transient protection
- Onboard PWR, TXD, RXD LEDs for easy monitoring of power and data status
- Supports Windows, Linux, Mac, Android, WinCE, and other operating systems
Specifications
| Parameter | Description |
|---|---|
| Product Type | Industrial‑grade isolated USB to RS485 converter |
| Host Interface | USB |
| Device Interface | RS485 |
| USB Connector Type | USB-A |
| USB Operating Voltage | 5 V |
| Communication Chip | FT232RNL |
| Data Rate | 300 bps ~ 512000 bps |
| RS485 Pins | A+, B‑, GND |
| RS485 Connector Type | Screw terminal |
| Direction Control | Hardware automatically controls data direction |
| RS485 Nodes | Point‑to‑multipoint, up to 32 nodes; more than 16 nodes recommend using a repeater |
| RS485 Transmission Distance | Approximately 1200 m at low baud rates |
| USB Transmission Distance | Approximately 5 m |
| RS485 Termination | Onboard 120 Ω balancing resistor |
| Interface Protection | 600 W surge/lightning protection, 15 kV ESD protection |
| Isolation Method | Optical isolation |
| Isolation Voltage | Up to 2.5 kV |
| Operating Temperature | -40℃ ~ 85℃ |
| Operating Humidity | 5%RH ~ 95%RH |
| Supported Operating Systems | Windows 11 / 10 / 8.1 / 8 / 7 / XP, Mac, Linux, Android, WinCE |
LED Indicator Descriptions
| LED Indicator | Status Description |
|---|---|
| PWR | Power indicator, lights when USB is connected and voltage is detected |
| TXD | Transmit indicator, lights when data is being sent from the USB port |
| RXD | Receive indicator, lights when data is returned from the RS485 device side |
Interface Description
| Interface | Description |
|---|---|
| USB‑A | Connects to host devices such as PC, industrial computer, Raspberry Pi, Jetson |
| A+ | RS485 differential signal A |
| B‑ | RS485 differential signal B |
| GND | RS485 side reference ground; recommended for long‑distance or multi‑node communication |
The USB TO RS485 (C) employs an isolated design. The isolation circuitry reduces ground loops and common‑mode interference between the USB host side and the RS485 bus side. The GND on the RS485 side is used as a bus reference ground and for noise immunity; it is not equivalent to directly shorting the field device ground to the computer USB ground.
Isolation and Protection
Isolated RS485 converters are suitable for scenarios where there are significant ground potential differences, many interference sources, long transmission distances, or many bus nodes. The isolation and protection design of the USB TO RS485 (C) includes:
- Optical isolation: reduces interference coupling between the USB host side and the RS485 field side
- TVS protection: suppresses surge voltages and transient spikes
- ESD protection: improves electrostatic discharge immunity during plugging/unplugging, wiring, and on‑site operation
- Resettable fuse: automatically recovers after an overcurrent fault, reducing maintenance costs compared to one‑time fuses
- 120 Ω termination: helps reduce signal reflections in long‑distance or high‑speed communication