Intended for use with portable and laptop PC's, these units bundle a USB hub with various interfaces - often some combination of USB to serial, parallel, PS/2 keyboard/mouse and LAN adapters in one package.

There are a few of these around, manufacturers include Targus and Kensington. Most target Win XP (and sometimes Win2000), so support for other operating systems is uncertain at best.

Each contains multiple devices and is best analysed by treating the individual USB devices separately. Compatibility of each individual component with Linux (or other non-Windows O/S) varies widely.

Targus Universal Docking Station w/ Digital Audio Model #acp45

This has not been tested, but Linux drivers for the individual devices within appear to be widely available. Targus itself provides no useful information as to whether the product works on Win9x or non-Windows operating systems.

Individual devices bundled into this unit are:

• 4-ports USB 2.0 hub, powered
• ASIX ax88772 USB 2.0 to Fast Ethernet Adapter
• Prolific 2313 USB-to-serial
• Prolific 2315 USB-to-parallel
• C-Media USB Audio with analogue and optical/SPDIF outputs
• a pair of PS/2 to USB HID keyboard/mouse interfaces

These can be used by handling the integrated unit as the individual devices above, using standard Linux drivers for each.

Test results so far for the Targus acp45 are:

• Under 2.4 kernels, USB 2.0 hub recognised, Prolific 2313 serial and 2315 parallel recognised, USB audio through USB 2.0 hub may be problematic (see SlugAsAudioPlayer as this is a more general issue with the 2.4 kernels), ASIX network interface not supported (as it needs a driver that's in 2.6). Note that there is no easy way to separate the audio adapter from the USB 2.0 hub as the USB docking station is one integrated multifunctional unit.
• Under 2.6 kernels, USB 2.0 hub, Prolific 2313/2315 serial/parallel ports, C-Media audio, ASIX network interface all appear to work well. HID remains to be tested. In general, the device appears fully compatible with the new kernels, using the stock usbnet.o, asix.o, usb-serial.o, pl2313.o, usb-printer.o, sound-core.o, usb-audio.o as standard drivers for various bundled devices in the acp45.

A general description of these various units is on www.targus.com/ca/accessories_cables_hubs.asp

Keyboard and mouse for all of these units would be using the standard USB human interface devices driver.

Targus Universal Notebook Docking Station with Video Model #acp50

This unit is very unlikely to be usable under any flavour of Linux; at a minimum, the video is proprietary and undocumented.

Based on mct.com.tw's proprietary interface, which consists of a USB interface + FIFO, an embedded processor and proprietary firmware driving the internal video interface hardware (described in U.S. patent #7203788 on uspto.gov). No documentation appears to exist as to what is communicated between the host and the firmware on this embedded processor; the chipset's manufacturer (mct.com.tw) is far too busy suing the manufacturers of competing USB-to-video adapters to be of any real help here.

Individual devices bundled into this unit (based on the Win2000 driver's .inf files for this box) are:

• MCT Corp USB 2.0 to SVGA (proprietary/undocumented interface)
• Admtek adm8515-series network interface
• Serenum Serial on USB converter (Philips)

The only Linux-supported VGA-USB interfaces (as of 2007) appear to be the sis315e chipset-based devices, see AddVGAAdapter and linux.die.net/man/4/sisusb for details. The video in this unit, as it uses another chipset, most likely will not work under Linux. Therefore, it will be best to avoid the integrated SVGA USB docking stations at the present time and choose the non-video equivalents, selecting one of the (rare) Linux-compatible USB video adapters separately.