It seems nearly every electronic gadget manufactured today makes use of the ever-handy USB port. Early computers featuring USB normally had only one or two ports located at the back of the case. Newer computers typically feature several built-in ports, and many cases now place two or more of them in front. Even so, additional ports are often needed, and having them conveniently accessible makes all the difference. The USB hub does just that.
A USB hub is a small, light unit with multiple ports for plugging in USB devices. It is commonly connected to a USB port located on the back of a desktop computer using an extension cable. Once the hub is plugged in, the user can set it wherever is convenient, avoiding the hassle of accessing the rear of the system. A hub is also great for laptops with only one or two ports. When linked up correctly, some hubs can support up to 127 devices.
A self-powered USB hub can be used to connect digital cameras, card readers, keyboards, mice, MP3 players, memory sticks and many other handheld USB devices. For more robust components, such as external drives, printers, scanners or fax machines, an AC-powered device is a better choice. Some of the AC-powered hubs come with an adapter, while others have the capability, but require the adapter to be purchased separately. When shopping for a hub, consumers should be sure to get one that will best meet his or her needs.
Another feature to look for what generation of USB the hub can use. Each subsequent generation operates at a speed faster than the previous. USB 1.1 is capable of data transfer speeds up to 12 megabits per second (mbps), while USB 2.0 can transfer data at 480 mbps, 40x faster. Released in 2008, USB 3 has a maximum speed of 625 megabytes per second (MBps).
A USB hub that supports later generations is often backward compatible, supporting earlier devices as well. The hub automatically detects and runs at the fastest rate the device will support. One that supports 3 cannot "push" a slower device to run faster than its design. Conversely, a hub that only supports 1.1 may or may not support a 2.0 device, but if it does, it will slow it down to 12 mbps — the fastest speed the hub supports.
Virtually all USB devices are plug 'n' play, or hot-swappable, but it's wise to be conservative with this feature when using an external hard drive with a USB port. Data could be lost due to software bugs or if the drive is unplugged while busy.
A USB hub is an inexpensive, handy addition to any system, especially useful with laptops that normally have too few native USB ports and older systems that have rear ports. They can be purchased in a four-port model, a seven-port model, or greater, and multiple hubs can be used for scalable growth.