interfaceguide.md

Which Interface Do I Use?

Not sure which interface to select? Follow these two steps.

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Step 1 - Check Device Manager on Windows

Plug in your adapter, then open Device Manager (Win + X → Device Manager).

Look under two places:

• Universal Serial Bus devices or libusb-win32 devices → your adapter shows as WinUSB Device, Candlelight, or similar - no COM port. Use gs_usb.

• Ports (COM & LPT) → your adapter shows as COMx (e.g. COM3, COM8). Go to Step 2.

On Linux/Mac, gs_usb devices appear as /dev/canX via SocketCAN. COM port devices appear as /dev/ttyUSBx or /dev/ttyACMx.

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Step 2 - Identify your COM port adapter

Run this script with your adapter plugged in (change PORT to your COM port):

import serial, time

PORT = "COM8"  # change to your port

for baud in [9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600, 2000000]:
    try:
        s = serial.Serial(PORT, baudrate=baud, timeout=0.5)
        time.sleep(0.1)
        s.write(b"V\r")
        time.sleep(0.1)
        resp = s.read(32)
        s.close()
        if resp:
            print(f"{baud}: {resp}")
    except Exception as e:
        print(f"{baud}: error - {e}")

Reading the result:

Response at the working baud rate	Interface to use
Starts with \xaa (e.g. b'\xaa\xc8...')	seeedstudio
Readable ASCII (e.g. b'V1010\r')	slcan
All \xff at every baud rate	Adapter may need a driver - check manufacturer

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Known devices quick reference

Device	Where it appears	Interface
FYSETC UCAN (STM32F072)	USB devices - no COM port	gs_usb
CANable 2.0 Pro (Candlelight firmware)	USB devices - no COM port	gs_usb
CANable 1.0 (Candlelight firmware)	USB devices - no COM port	gs_usb
CANable 1.0 (slcan firmware)	COM port	slcan
GY USB-CAN Analyzer	COM port	seeedstudio
Seeed Studio USB-CAN Analyzer	COM port	seeedstudio
Cheap "USB CAN Analyzer" from Amazon/AliExpress	COM port	seeedstudio (most likely)
PEAK PCAN-USB	CAN-Hardware in Device Manager	pcan
Kvaser	CAN-Hardware in Device Manager	kvaser
No hardware	-	virtual

CANable 2.0 clones - CANable 2.0 Pro ships with Candlelight firmware (gs_usb). Cheaper clones may ship with slcan firmware instead. Check Device Manager - if it shows a COM port, use slcan.

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Still not sure?

Open an issue on GitHub with:

• The device name / Amazon listing name / Web Link
• Output of the identification script above

We will identify it and add it to the table.