Featured Products

  Featured Products Defined:

Universal Serial Bus (USB) is a serial bus standard to interface devices to a host computer. USB was designed to allow many peripherals to be connected using a single standardized interface socket(USB Cable) and to improve the plug-and-play capabilities by allowing hot swapping, that is, by allowing devices to be connected and disconnected without rebooting the computer or turning off the device. Other convenient features include providing power to low-consumption devices without the need for an external power supply and allowing many devices to be powered using a USB Cable.

USB Cables replace many legacy varieties of serial and parallel cables. USB cables are used to connect computer peripherals such as mouse, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, and flash drives. For many of these devices USB Cables have become the standard connection method. USB Cables were originally designed for personal computers, but it has become commonplace for other devices such as PDAs and video game consoles to use a USB Cable. Another popular use of USB Cable are as a bridging power cord between a device and an AC adapter plugged into a wall plug for charging purposes. As of 2008, there are about 2 billion USB devices in the world.

USB Cable Connector Types:

The Standard-A type of USB connectors takes on the appearance of flattened rectangles that plugs into downstream-port sockets on the USB host or a hub. This kind of connector is most frequently seen on USB cables that are permanently attached to a device, such as one on a USB cable that connects a keyboard or mouse to the computer. Standard-B connectors look square with beveled corners, and plugs into upstream sockets on devices and hubs. The Standard-B connector is mainly used only for the device end of a removable USB cable, such as between a hub and a printer.

Mini-B, Micro-A, and Micro-B connectors are used on USB Cables for smaller devices such as PDAs, mobile phones or digital cameras. The Standard-A plug is approximately 4 by 12 mm, the Standard-B approximately 7 by 8 mm, and the Mini-A and Mini-B plugs approximately 2 by 7 mm. So when looking for a USB cable please make sure to check out the ports on your printer, camera or PDA to make sure you get a USB Cable with the right connections.

The maximum length of a standard USB cable is 5.0 meters (16.4 ft). The primary reason for this limit is the maximum allowed round-trip delay of about 1500 ns. If a USB device does not answer to host commands within the allowed time, the host considers the command to be lost. When adding up the USB device response time, delays from using the maximum number of hubs, and delays from the connecting USB cables, the maximum acceptable delay per USB cable turns out to be 26 ns. The USB 2.0 specification requires USB cable delay to be less than 5.2 ns per meter (which is close to the maximum achievable speed for standard copper cable). This allows for a 5 meter USB cable.

Human-interface devices (HIDs)

Mice and keyboards are frequently fitted with USB connectors, but because most PC motherboards still retain PS/2 connectors for the keyboard and mouse as of 2007, they are often supplied with a small USB-to-PS/2 adaptor, allowing usage with either USB or PS/2 interface. There is no logic inside these adaptors: they make use of the fact that such HID interfaces are equipped with controllers that are capable of serving both the USB and the PS/2 protocol, and automatically detect which type of port they are plugged into. Joysticks, keypads, tablets and other human-interface devices are also progressively migrating from MIDI, PC game port, and PS/2 connectors to USB.

Apple Macintosh computers have been using USB exclusively for all external wired mice and keyboards since January 1999. The original iMac raised public awareness of USB considerably in August 1998, as it discarded legacy ports to use only USB. PCs had USB ports prior to the iMac's introduction, but they were included with a full complement of traditional ports which slowed down USB's adoption. The iMac's influence can be seen in the number of USB peripherals with matching translucent, colored plastic enclosures that were available in the late '90s and early '00s.

USB Cables