WSAL21550 – USB TO TTL (B)/en

Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

Summary

The Waveshare USB TO TTL (B) is an industrial converter that translates a USB interface into a serial TTL UART port. It uses the original CH343G chip and provides over-current, over-voltage, reverse-polarity and ESD protection plus selectable TTL level options.

Related products at JW Tech

• WSAL21550 – Industrial USB TO TTL Converter, Original CH343G Onboard, Multi Protection & Systems Support

Technical overview

• Component: original CH343G as USB-to-serial adapter
• Interfaces: USB Type-A on the host side; 6-pin right-angle pin header for UART
• Supply voltage: 5 V
• Communication rate: 50 bps up to 6 Mbps
• TTL levels: 5 V / 3.3 V selectable via jumper cap; 2.5 V / 1,8 V only through external voltage input
• Protection circuitry: resettable fuse, TVS diode, IO protection diodes against surges
• Indicators: three LEDs - PWR (red when USB voltage detected), TXD (red while sending), RXD (red while receiving)
• Enclosure: plastic case with matte finish; IDC connector with fool-proof design

Commands and examples – verify before use: 

ls /dev/tty*
minicom -D /dev/ttyACM0

Notes and version constraints

• Using 2.5 V or 1.8 V requires external power injection; verify the exact wiring on site.
• Windows 7 may show a digital signature warning during driver installation; resolving it requires downloading a repair tool - confirm the source of the tool.
• Linux/Raspberry Pi usage is driver-free, but the exact device path name (e.g., ttyACM0) should be verified before use.
• On macOS, the manufacturer driver must be installed; installation steps are version-sensitive and should be confirmed by a professional.
• Android usage requires installing a specific app; availability and compatibility with your device must be checked.
• Inferior knock-offs exist in the market without testing; purchase only through official channels.

Source and revision record

• USB TO TTL (B) - Waveshare Wiki
• Source revision: 108919
• Captured: 2026-09-03T02:56:24+00:00
• SHA-256: f6927cdf55576a4b780041fbc16c8c2aa836937d3c52c72b63aaf2634874a1d4