Virtual CD-ROM switching utility
| Industry | Telecommunications hardware |
|---|---|
| Products | ZeroCD (virtual CD-ROM switching technology) |
Virtual CD-ROM switching tools refer to software applications created to deactivate the virtual CD-ROM drives embedded in devices such as mobile broadband modems. These tools handle "flip flop" (multi-function) USB devices, which are frequently employed in high-speed wireless WAN hardware that initially present themselves as USB flash drives containing necessary drivers. After driver installation, a specific command changes the device’s operational mode, substituting the virtual CD-ROM or mass storage device with the actual modem component. The WWAN manufacturer Option markets this technology under the name "ZeroCD (TM)." Execution of this switch requires an operating system compatible with the device’s driver.
By utilizing USB monitoring utilities and libusb, developers can capture and duplicate the command responsible for triggering the mode change, enabling its use in unsupported platforms. This permits virtual CD-ROM switching software to mimic the command, converting the device from storage mode to modem mode, unmounting any software disks, and establishing a modem interface (typically ) for network control.
Operating systems compliant with USB standards, such as Linux, include drivers that recognize 3G devices as USB serial interfaces alongside storage devices as USB mass storage units. Devices lacking proprietary drivers may rely on these generic drivers. Moreover, virtual CD-ROMs found on U3-compatible hardware can be removed through dedicated software solutions. Certain 3G modems, including those from Huawei, allow complete deactivation of their virtual CD-ROM feature.
Prominent software tools in this domain include:
- ZeroCD: Devices equipped with ZeroCD initially present themselves as USB CD-ROM drives containing Windows drivers and control applications. Following driver installation, a USB command transitions the device into modem mode.
- Ozerocdoff: This tool temporarily disables ZeroCD on Option WWAN USB modems, which enumerate as virtual CD-ROMs labeled "ZOPTION." It facilitates switching off ZeroCD to enable modem operation.
- USB_ModeSwitch: A utility designed to toggle virtual CD-ROM devices; starting with version 1.0.3, it integrates with udev for automatic device switching.
- Switch2modem: Created specifically for switching 3G USB modems under OpenSolaris.
- Fetch utility (huaweiAktBbo.c): Implements Windows-style USB communication for Huawei devices through source compilation.
These utilities improve cross-platform compatibility and functionality of mobile broadband modems by controlling virtual CD-ROM behavior essential for driver deployment and device activation.