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Docs USB & Connectivity USB Connection Guide

USB Connection Guide

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How to connect the beacon to a computer or phone over USB: ports, cables, drivers and what you can do once connected.

USB Connection Guide

The beacon’s only wired interface is USB. Over that one cable you can flash firmware, watch debug logs, run serial commands, and stream GPS positions to the website through the serial bridge. This page covers the connection itself.

What the USB port is

The ESP32 DevKit V1 exposes its UART through an onboard USB-serial chip. From the computer’s point of view the beacon looks like a serial port, not a disk or a network device. Two common chips are used:

  • CP2102 / CP210x (Silicon Labs) on most DevKit V1 boards.
  • CH340 on many clones.

The chip matters only for drivers. See CP210x Driver Install and CH340 Driver Install.

The three USB jobs

One cable, three uses, no replugging needed:

JobHow
Flash firmwarepio run -t upload (PlatformIO) or esptool over the same port
Talk to the deviceAny serial monitor at 115200 baud (see Serial Monitor Guide)
Report positionsRun bridge/aegis-serial-bridge.py; the bridge reads the same port

Cable checklist

  • Use a data cable. Many cables sold for charging only carry power; the beacon will light up but never appear as a serial port.
  • Short, decent-quality cables are more reliable for flashing. Long thin cables can drop bytes during uploads.
  • USB 2.0 is plenty; nothing here needs USB 3 speeds.

Port naming

OSTypical nameNotes
WindowsCOM3, COM5See Device Manager under Ports (COM and LPT)
macOS/dev/cu.usbserial-* or /dev/cu.usbmodem*The cu. variant is the one to use
Linux/dev/ttyUSB0 or /dev/ttyACM0Check ls /dev/tty* before and after plugging in

See Serial Port Detection for finding the exact name.

First connection

  1. Plug the beacon in with a known-good data cable.
  2. Install the driver for your USB-serial chip if the port does not appear.
  3. Open a serial monitor at 115200 baud and press the EN button on the board.
  4. You should see the boot banner and the AEGIS:HELLO:ver=5.5;... line.

If nothing appears, go to Serial Adapter Troubleshooting.

Phones

Android phones can drive the beacon over USB with an OTG adapter; iOS devices cannot run a serial terminal or the bridge, but can still open position links. See Android OTG Guide and Termux Serial Bridge.