Why does my telemetry radio not show up as a COM port?

Usually the driver is missing. An uninstalled CP2102 appears in Device Manager under Other devices with a warning icon rather than under Ports, which is the signature to look for. The other common cause is a charge-only USB cable, which looks identical to a data cable and produces no device at all.

Which driver does my device need?

The one matching the USB-to-serial chip, not the product. A CP2102 needs the Silicon Labs CP210x driver, and a CH340 or CH341 needs the WCH driver. Devices reached through a USB-to-TTL adapter take whatever the adapter's chip needs, regardless of what is plugged into the other end of it.

Where should I download the CP2102 driver from?

From Silicon Labs, who make the chip. Their CP210x VCP driver package is the authoritative source and covers current Windows versions. Driver downloads are a well-known target for bundled unwanted software, so the manufacturer's own page is the one to use.

The driver installed but the device still has a warning icon

Remove the device in Device Manager, unplug it, and install the driver again before reconnecting — a half-finished or mismatched installation can leave the entry stuck. If it persists, restart Windows and check again, and confirm the chip really is a CP2102 rather than a CH340.

CP2102 Driver Installation Guide (Windows)

The CP2102 is a USB-to-UART IC from Silicon Labs, used on several MicoAir telemetry products such as the LR900-F and LR24-F. The first time you connect a MicoAir radio to a Windows computer, you need to install the CP2102 driver.

Recommended: Silicon Labs official CP210x VCP Drivers — download the Windows package directly from the chip manufacturer.

Mirror: MicoAir CP2102 driver package

Step 1

Connect the radio (LR900-F/P, LR24-F/P, etc.) to the computer via USB and open Windows Device Manager. Under Other devices you'll see a CP2102 device with a warning (!) icon — this means the driver isn't installed yet.

CP2102 device with warning icon

Step 2

Right-click "CP2102 USB to UART Bridge Controller" and choose the first option, "Update driver."

Update driver

Step 3

Choose "Browse my computer for drivers."

Browse my computer for drivers

Step 4

Click "Browse," locate the folder containing the driver files, then click "Next."

Browse to the driver folder

Step 5

The CP2102 driver installs automatically; after a few seconds you'll see a screen indicating it installed successfully.

Driver installed successfully

Step 6

Once installed, you'll see the "Silicon Labs CP210x USB to UART Bridge" device under Ports in Device Manager, along with the COM port number assigned to it (e.g. COM4). You'll need this port number when connecting to the radio in your GCS software.

CP210x device with assigned COM port

MicoAssistant Guide — which driver each device needs, and what to do when no port appears
ArduPilot — Telemetry Setup Guide
PX4 — Telemetry Setup Guide
LR900 Telemetry Radio — User Manual
LR900 Web Configurator

Where to buy

Radios that use the CP2102 chip this driver is for, shipped from Canada with free Canada-wide shipping:

MicoAir LR900-F — 915 MHz telemetry pair
MicoAir LR900-P — 915 MHz, 1 W
MicoAir LR24-F — 2.4 GHz telemetry pair

Written and maintained by the Robofusion engineering team.

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Related guides​

Where to buy​