USB cables and connectors are used to connect several devices to a computer. Different computer peripherals and accessories such as the monitor, keyboards, web cameras, microphones, printers, scanners, speakers, and even external hard drives are connected to the computer CPU through cables and connectors. More so, electronic devices and gadgets can also be connected to the computer through cables and connectors. These connectors allow the transfer of data—both sending and receiving—from and to the computer and the external device or gadget. Some cables are also used for charging different devices.
Standard USB cables have two ends, namely the receptacle or the female end and the plug or the male end. The plug is the connector that is attached to the computer. The receptacle is the connector mounted on the host or the device. The plug is the rectangular connector. The receptacle is usually a square connector that is common in printers and portable hard drive. A USB icon is required to be embossed on the “topside” of every plug do as to avoid inserting the plug incorrectly to the computer. The USB icon should also be shown adjacent to every receptacle. These requirements help in identifying how the connectors should be inserted in the USB port of the computer and in the device or gadget.
Each USB cable connector has four pins—two pins are used for power and the other two pins are used for data transmission. The pins for power connection are generally longer than the pins for data transmission. This is to allow the cable to connect the power supply first, and then establish the data connection afterwards. This sequence lessens the risk of transferring possible dangerous voltage that might destroy the computer and/or the gadget.
However, the release of new devices and gadgets gave way to the introduction of new forms of cables and connectors. Mini-USB and Micro-USB cables are introduced to allow the connection and transfer of data between computers and media players, cameras, and smartphones. Both of these versions of USB connectors have an extra pin called the ID. In the Mini-USB connectors, the ID pin is normally not connected and was added for future improvements to be introduced to the USB standard. On the other hand, the ID pin in the Micro-USB connectors work as an A or as a B connector.
Mini-USB cable connectors are developed to cater the need to improve the connection and communication between a computer and small gadgets like digital cameras and mobile telephones. Since these gadgets are much smaller in size than the computer, it is impractical to have the standard USB port in these gadgets. Thus, there is a need for smaller port and smaller USB cable connector. This gives way to the introduction of Mini-USB cable connectors. With the same functionality as that of the standards rectangular and square connectors, the Mini-USB connecters was well-received by gadget manufacturers.
In 2007, Micro USB cable connectors were released. These USB cables are made for the smaller and thinner gadgets that are recently made available to the public. These smaller cables are specially design to last longer than its mini-USB counterpart, it can be used for more than 10000 connect/disconnect cycles. Micro-USB connectors also allow small devices and gadgets to both act as a master and a slave when connected to a computer. The USB cable connectors allow the device to easily switch from master to slave and vice versa. This technology is called USB On-The-Go or USB OTG. Because of these improvements in the USB cable technology, Micro-USB connectors became widely used in smartphones, PDAs, and cellular phones.
Today, USB cables or Universal Serial Bus Connectors are categorized as USB 2.0 Type A, USB 2.0 Type B, USB 2.0 Mini Type B 4 Position, USB 2.0 Mini Type B 5 Position, USB 2.0 Micro B, USB 3.0 Type A, USB 3.0 Type B, and USB 3.0 Micro Type B.