04c1:3021 — 56k Voice FaxModem Pro

This is the USB identifier for a 56k Voice FaxModem Pro manufactured by U.S. Robotics (3Com). The vendor ID 04c1 is registered to U.S. Robotics (3Com) with the USB Implementers Forum, and 3021 is the product ID that U.S. Robotics (3Com) assigned to this particular model. When you run lsusb on Linux, this device appears as 04c1:3021 U.S. Robotics (3Com) 56k Voice FaxModem Pro.

Linux

$ lsusb
Bus 001 Device 004: ID 04c1:3021 U.S. Robotics (3Com) 56k Voice FaxModem Pro

You can filter directly with lsusb -d 04c1:3021, or get the full descriptor dump with lsusb -v -d 04c1:3021. Kernel messages from dmesg show the same pair as idVendor=04c1, idProduct=3021.

Windows

In Device Manager, open the device, go to Details → Hardware Ids. This device reports:

USB\VID_04C1&PID_3021
USB\VID_04C1&PID_3021&REV_0100

From PowerShell: Get-PnpDevice | Where-Object InstanceId -match "VID_04C1&PID_3021"

macOS

$ system_profiler SPUSBDataType
    56k Voice FaxModem Pro:
      Product ID: 0x3021
      Vendor ID: 0x04c1  (U.S. Robotics (3Com))

Having driver issues with this device? Most USB devices are handled by a generic class driver; if yours shows up as an unknown device, confirm the ID above first, then check the manufacturer's downloads page.

The exact lines this page is generated from, in the upstream source file:

04c1  U.S. Robotics (3Com)
	3021  56k Voice FaxModem Pro

• 04c1:0097 OfficeConnect Analog
• 04c1:009d HomeConnect Webcam [vicam]
• 04c1:00a9 ISDN Pro TA-U
• 04c1:00b9 HomeConnect IDSL Modem

See all 10 devices from U.S. Robotics (3Com) →