Apple introduced the PowerBook Duo Dock Plus on May 15, 1995. The Duo Dock Plus replaced the Duo Dock II. The Duo Dock is used to turn a PowerBook Duo subnotebook into a fully functioning desktop computer. PowerBook Duos have only two built-in ports: an optional RJ-11 modem port and a serial port for a printer or external modem. The Duo Dock adds an optional internal hard drive, 1.4 MB floppy disk drive, and a wide array of standard Macintosh and PowerBook ports. With this docking solution, when you want to take your work with you, you simply press the eject button on the Duo Dock Plus and the PowerBook Duo laptop slides out, ready for computing wherever you go. The Duo Dock Plus originally cost $900. We acquired our Duo Dock Plus for $25 in 2008.

The floppy disk drive is located on the right side of the Dock

The Apple Macintosh PowerBook Duo Dock Plus turns a PowerBook Duo into a full-featured desktop Macintosh. The Duo Dock Plus is very similar to the older Duo Dock II, and it has the same optional 230 MB hard drive. However, the newest Duos at the time couldn't make use of the Dock II's 32K level 2 cache and its built-in FPU, so Apple dropped them in the Plus. The Dock II's standard 68882 FPU and level 2 cache are not utilized when used with the PowerPC-driven PowerBook Duo 2300c and the 68LC040 processors of the PowerBook Duo 280 and 280c. The original Duo Dock, the Duo Dock II's immediate predecessor, had an optional FPU, which did not ship as standard equipment. Like the Duo Dock II, the Duo Dock Plus' notebook enclosure is larger than the original Duo Dock, providing compatibility with newer PowerBook Duos with thicker color displays. Also like the Duo Dock II, the Plus has a hinged door on front. The original Duo Dock does not have this door.

The Duo Dock Plus has an auto-inject and -eject one-step docking device, similar to the mechanism used in an older VCR (Video Cassette Recorder) that accepts a closed PowerBook Duo. A key is provided to lock the PowerBook Duo in place for security purposes. The PowerLatch docking technology provides an easy, reliable connection between the Duo Dock and the PowerBook Duo subnotebook. The PowerLatch pulls in the PowerBook and connects its 152-pin Processor Direct Slot (PDS) to the Duo Dock. The Duo Dock uses the PowerBook's processor, but adds its own set of standard Macintosh and PowerBook ports, increased amount of VRAM, internal floppy disk drive, and two NuBus slots for expansion. The Duo Dock has an internal expansion bay for an optional 50-pin SCSI hard drive. The Duo Dock doesn't have any additional RAM nor does it have its own built-in processor.

PowerBook Duo subnotebook inserted into the Duo Dock Plus

The Duo Dock Plus has the following built-in ports: one ADB port, one DB-15 video port, one HDI-30 SCSI port, one AAUI-15 Ethernet port, one serial external modem port, one serial printer port, one internal modem port (RJ-11), one sound-in jack, and one sound-out jack.

PowerBook Duo Dock Plus ports

The Duo Dock Plus has 1 MB of built-in VRAM. It is capable of driving an external monitor over a variety of resolutions beginning with 512 x 384 (16-bit color depth) and ending at 1152 x 870 (8-bit color depth). The minimum and maximum resolutions possible depend on the type of monitor used. Typically, 1 MB of VRAM translates into thousands of colors on 17-inch displays and 256 colors on 20- and 21-inch displays. 21 inches is the maximum display compatible with the Duo Dock Plus. The Duo Dock Plus supports most Apple displays, including the Apple Multiple Scan 20 Display (19.1-inch diagonal viewable image size), as well as most VGA and SVGA displays.

The Apple PowerBook Duo system was an excellent choice for users who wanted an extremely small but powerful portable computer that could be turned into a full Macintosh desktop system. At the heart of the PowerBook Duo system was the award-winning PowerBook Duo subnotebook computers. Weighing less than 5 pounds, they were light enough to take anywhere. But the PowerBook Duo and Duo Dock was not a huge success for Apple and sales were never near that of the very successful PowerBook line.

The Duo Dock Plus was the last Duo Dock sold by Apple. It was quietly retired on February 1, 1997. The full-sized desktop dock / subnotebook concept had run its course at Apple. Miniaturization had begun to reach the point where consumers just couldn't justify buying a pricey dock to use with a pricey subnotebook that had almost no ports and no built-in floppy or CD drive of its own.

Video Gallery

See Vectronic's Duo Dock Plus in action:

See more Apple-related videos in Vectronic's Apple Video Gallery.

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