The 3Com 3C920 Integrated Fast Ethernet Controller (3C905C TX Compatible) driver enables Windows to communicate with the computer’s built-in wired network adapter. A compatible driver helps the system recognize the controller and use its Ethernet connection for local network access and internet connectivity.

Key Features

• Hardware recognition: Identifies the 3Com Ethernet controller in Windows so the operating system can configure and use the adapter.
• Fast Ethernet connectivity: Supports the controller’s 10/100 Mbps wired networking capabilities when connected to compatible network equipment.
• Network configuration access: Makes supported adapter settings available through Windows networking tools and Device Manager.
• Driver recovery: Can help restore adapter functionality when an existing driver is missing, damaged, or incorrectly matched to the hardware.

How to Install

1. Confirm the adapter model. Open Device Manager and look under Network adapters or Other devices. Check the device’s hardware IDs in Properties > Details if the controller is unidentified. Match these IDs against the driver package’s supported hardware list.

1. Check Windows compatibility. Before downloading a package for Windows 11, 10, 8, or 7, verify that it explicitly supports your Windows version and system architecture. This is a legacy 3Com controller, so compatibility with newer Windows releases should not be assumed from the device name alone.

1. Prepare the driver files. Download the matching package and extract it if necessary. If this computer has no working network connection, use another computer to download the files and transfer them with a USB drive.

1. Install the driver. Run the included installer, if provided. Otherwise, right-click the controller in Device Manager, select Update driver, choose Browse my computer for drivers, and point Windows to the extracted folder. Do not force installation if Windows reports a compatibility or signature problem.

1. Restart and test the connection. Restart if prompted, connect an Ethernet cable, and check that the adapter appears without a warning icon. If connectivity remains unavailable, inspect the cable, router or switch port, and Windows network settings before replacing the driver again.

Common Issues and Fixes

• Install fails or driver is rejected: The 3C920/3C905C TX driver is legacy and may be unsigned or lack an INF entry for your exact hardware ID. Install manually via Device Manager → Update driver → Browse, and use compatibility mode for older Windows if needed.
• Device not detected: Confirm onboard LAN is enabled in BIOS/UEFI and not disabled by a “LAN disable” jumper or security setting. In Device Manager, check for an unknown Ethernet controller or hidden device, then scan for hardware changes.
• Version conflicts after upgrading Windows: Remove any existing 3Com adapter driver first, reboot, and install only one 3C920/3C905C-compatible package. Avoid mixing generic and vendor drivers; roll back if Windows replaces it with an incompatible version.