Choosing the Right Solution for More USB Ports
If you can’t find any “hidden” USB ports, you have the following options:
- Add a card containing USB ports to your desktop or notebook computer
- Add a USB hub
Let’s discover when each solution makes sense.
The Add-on Card Solution
You can add anywhere from two to as many as five USB ports to a desktop computer by installing a card. By adding a card, you don’t sacrifice a USB port as you would if you used a USB hub, which also helps unclutter your desk.
Most recent desktop computers can use either PCI or PCI Express cards; PCI Express is preferred, as it provides better system performance and many systems have empty PCI Express slots. If you want to “future-proof” your system by adding USB 3.0 support, PCI Express (aka PCIe) is the way to go. Figure 7 compares PCI and PCI Express x1 slots.
Figure 7 Most recent systems have more PCI Express x1 slots than PCI slots.
Notebook computers can also add two or more ports by means of the now-obsolete PC Card CardBus slot or the current ExpressCard slot. See the ExpressCard website for a visual comparison of CardBus and ExpressCards.
Why Buy a Bus-Powered Hub?
If you have decided that you’d rather just buy a USB hub, you have two choices: bus-powered or self-powered. Bus-powered hubs are ideal when you’re looking for a low-cost way to connect standard low-power (100mA or less) devices such as keyboards, mice, printers, game controllers, all-in-one units, and external hard disks that use AC adapters for power.
You can pick up a USB 1.1 bus-powered hub (often identified as simply a “USB hub”) if all you want to connect are input devices such as keyboards, mice, and game controllers – all of which actually run at a mere 1.5Mbps. However, USB 2.0 (aka Hi-Speed USB) bus-powered hubs are more versatile. If you use a USB 1.1 hub with USB 2.0 devices, you will see an error message similar to the one in Figure 8, and your USB 2.0 devices will be limited to 12Mbps (a big drop from 480Mbps!).
Figure 8 Windows knows when a USB 2.0 device is plugged into a USB 1.1 port or USB 1.1 hub.
When Bus-Powered Hubs Won’t Suffice
Unfortunately, the most common migratory USB devices (the ones you move from PC to PC) are the least likely ones to work with bus-powered hubs. These include USB flash drives (typically consuming 200mA or more) and portable USB hard disks (typically consuming 500mA). If you’re looking for a convenient place to plug these in, you really need a self-powered hub.
Why Buy Self-Powered Hubs?
I favor self-powered hubs that run at the fastest USB speed supported by your system (typically, USB 2.0) for several reasons: they provide enough power for virtually any USB device so you can’t damage a high-powered device by plugging it into the hub, low-power devices work just as well, and if you only need to plug low-power devices into the hub, most four-port self-powered hubs work fine as bus-powered hubs if you don’t use the AC adapter. I carry a compact four-port self-powered hub with my notebook computer, but in my office, I use a seven-port self-powered hub (Figure 9).
Figure 9 A seven-port self-powered hub provides plenty of room for an expanding population of USB devices.