Medius - Native APITransport

Transport

USB-serial port

The box enumerates as a USB-serial device, so it appears as an ordinary serial port. Everything travels over that port as raw bytes. Open the port at the fixed baud, then send frames and confirm the box with the handshake.

Serial link

Baud and framing

Fixed 4,000,000 baud (4 Mbaud), no negotiation. Open the port at that exact baud and start sending bytes; any other baud fails.

The box speaks framed binary from the first byte. There is no legacy startup path:

  • No ASCII console.
  • No 115200 startup step.
  • No baud-switch frame.
  • Baud is never saved on the box, so a bad setting can't lock you out.

USB identity

WCH CH343 bridge

A WCH CH343 chip does the USB-to-serial conversion. Match on its vendor and product IDs to pick the box out from other serial devices.

PropertyValue
VID0x1A86
PID0x55D3
Baud4,000,000
Framing8N1
Linux path/dev/ttyACM*
Windows pathCOMx

8N1 is 8 data bits, no parity, 1 stop bit.

See Connection for the handshake and Frame Format for the wire format.