USB to RS-485 Converter 101-0020 - Rugged Field Interface

Our review of the USB to RS-485 Converter 101-0020 finds it is a practical, no-nonsense adapter for technicians and engineers who need a rugged, plug-and-play link between a laptop USB port and 2-wire RS-485 equipment. The biggest reason to buy is its reliable field-oriented design: powered from USB with auto transmit control and a 7V common mode tolerance, it handles ground differences and live insertion without special host signals. This makes the unit especially useful when working on industrial networks where robustness and simplicity matter.

Key Features

• Auto transmit control: Automatically switches between receive and transmit so host software sees a serial port without manually toggling RTS.
• Live insertion safe: Power up/down glitch-free design allows connecting or removing the adapter while the system is live without causing bus disruptions.
• USB powered: Draws power from the USB port so no external power supply is required for most field tasks.
• Wide common mode range: Permits a 7V ground difference so it copes with many industrial grounding scenarios without signal loss.
• Rugged enclosure: Rubber and stainless steel housing resists rough handling and makes it suitable for onsite troubleshooting.
• Low power design: Minimal USB power draw helps preserve portable computer battery life during extended field use.

Who It's For

This converter targets field engineers, technicians, and integrators who need a compact, dependable interface for 2-wire RS-485 devices and prefer a buffer that tolerates ground offsets. It is ideal when quick, repeatable connections are required and when carrying an external power brick is impractical.

Those who need built-in bus termination or multiport isolation should look elsewhere, since the 101-0020 is not bus terminated and is designed as a single-port converter rather than a managed network node.

Pros & Cons

Pros

• Auto transmit control eliminates the need for RTS wiring, simplifying software integration.
• Wide 1000V common mode range tolerance (7V practical ground difference) improves reliability on unsteady grounds.
• Rugged rubber and stainless steel enclosure suits field service and rough use.
• USB power and low power consumption make it convenient for mobile use without extra adapters.

Cons

• Not bus terminated, so users must add termination externally when required by the network.
• Single-port design may be limiting for applications that need multiple simultaneous RS-485 channels.

Specifications

Product	101-0020 USB to RS-485 Converter
Power	Powered from USB port
Common mode range	1000V common mode range (permits ~7V ground difference)
Transmit control	Auto transmit control (no RTS required)
Enclosure	Rubber and stainless steel
Compliance	FCC, CE approved; RoHS compliant
Cable length	20cm cable

Our Verdict

The 101-0020 USB to RS-485 Converter is a sensible, value-oriented tool for technicians who need a rugged, USB-powered bridge to 2-wire RS-485 systems. Its auto transmit control, live insertion safety, and wide common mode tolerance make it especially useful in industrial troubleshooting and field commissioning where reliability and simplicity are priorities.

Frequently Asked Questions

Does this converter need an external power supply?
No, it is powered from the USB port so no external power supply is required for normal operation.

Will it handle ground differences between devices?
Yes, the common mode range permits ground differences (practical tolerance around 7V) to reduce communication issues on poorly grounded systems.

Is bus termination included?
No, the unit is not bus terminated so termination must be added externally when the network topology requires it.