USB (Universal Serial Bus)
Short for Universal Serial Bus, USB is a plug
and play interface that allows a computer to communicate
with peripheral and other devices. USB - connected devices cover a
broad range; anything from keyboards and mice, to music players and flash
drives. USB may also be used to send power to certain devices, such as
smartphones and tablets, as well as charge their batteries. The Universal
Serial Bus industry standard was established in 1995, and then quickly
adopted by Intel, Compaq, Microsoft and other companies.
Where are the USB ports ?
All modern computers have at least one USB port, below are the
typical locations you can find a USB port on a computer.
- Desktop computer - A desktop computer usually has two to four ports in the front and two to eight ports in the back.
- Laptop computer - A laptop computer has between one and four ports on the left, right, or both sides of the laptop.
- Tablet computer - If a tablet has a USB port it is usually the same port as the charging port. A few laptops may have an additional port and if it is available it is on one of the sides of the tablet.
- Smartphone - Not many smartphones have a USB port, but many use a USB port to charge the phone that can be used as a USB port when not being charged.
USB transfer speeds
- USB 1.x, is
an external bus standard that supports data transfer rates of 12 Mbps and
is capable of supporting up to 127 peripheral devices. The picture shows an example
of a USB cable being connected into the USB port.
- USB 2.0, also known as Hi-speed USB, was developed by
Compaq, Hewlett Packard, Intel, Lucent, Microsoft, NEC and Phillips and was introduced in 2001. Hi-speed USB is capable of
supporting a transfer rate of up to 480 megabits per second (Mbps), or 60 megabytes per second (Mbps), and is backwards
compatible, meaning it is capable of supporting USB 1.0 and 1.1 devices and
cables.
- USB 3.0, also known as Super Speed USB, was first made
available in November 2009 by
Buffalo Technology, but the first certified devices weren't available until
January 2010. USB 3.0 improved upon the USB 2.0 technology with speed and
performance increases, improved power management and increased bandwidth
capability (providing two unidirectional data paths for receiving and sending
data at the same time). USB 3.0 supports transfer rates up to 5.0 gigabits per second (Gbps), or 640 megabytes
per second (Mbps), and following the release of USB 3.1, has been renamed to
USB 3.1 Gen1 (for marketing purposes). The first certified devices included
motherboards fromASUS and Gigabyte Technology. Dell began
including USB 3.0 ports in their Inspiron and Dell XPS series of computers in
April 2011.
- USB 3.1, also known as Super Speed +, was made
available as of July 31, 2013 and is the latest version of the USB
protocol. USB 3.1 is capable of transfer rates of up to 10 Gbps, putting it in
line with the first generation of Apple's Thunderbolt channel. Today, many devices use the
USB 3.0 and 3.1 revisions for improved performance and speed.
- USB Type-C was
developed around the same time as USB 3.1 and is a reversible-plug, 24-pin,
double-sided connector for use with USB devices.
USB Connector Variations
USB connectors come in many shapes and sizes as there are many
different devices that utilize them. Every version of USB connector including
standard, Mini, and Micro have two or more variations of connectors.
USB cables - Length and
Type
USB cables are available in multiple lengths, from around 3 feet
to just over 16 feet in length. The maximum length of a USB cable is 16 feet 5
inches (5 meters) for high-speed devices and 9 feet 10 inches (3 meters) for
low-speed devices. These maximum lengths are due to data transfer timing and
the risk of data loss if using longer cable lengths. However, by using USB
hubs, you can connect two USB cables together to effectively extend the
distance between the two devices being connected.
There are different types of USB cables as well. As mentioned
above, there are different transfer speeds (2.0 and 3.0) for USB. Similarly,
there are different types of USB cables to match with those speeds. You can get
a USB 2.0 cable for use with a device using USB 2.0 or a USB 3.0 cable for use
with a device using USB 3.0.
There are also USB extension cables that can connect to one end
of a USB cable (typically the end that would connect to the computer) to extend
the length of the cable. However, you should still avoid extending the cable
beyond the 16 feet 5 inches total maximum length limit, unless using a USB hub
to connect another USB cable.
USB Devices
Today, there are
millions of different USB devices that can be connected to your computer. Below
are just a few of the most common USB devices you'll likely find and use.
- Digital Camera
- External drive
- iPod or other MP3 player
- Keyboard
- Keypad
- Microphone
- Mouse
- Printer
- Joystick
- Jump drive aka Thumb drive
- Scanner
- Smartphone
- Tablet
- Webcams
