Universal Serial Bus (USB)
A Universal Serial Bus (USB) cable is primarily designed to connect a USB device to a host, with common hosts including computers and video game consoles. USB cables come in various standards, but those compliant with USB 1.1 specifications are generally compatible with USB 2.0 technology, and vice versa. The cables are identifiable by the USB trident logo on the plug over molds of type “A” and “B” connectors.
Types of USB Connectors
USB cables can feature different types of plug ends, known as connectors. Connector types include Standard-A, Standard-B, Mini-B, Micro-A, Micro-B, and Micro-AB. These plugs correspond to receptacles in hosts and devices. For example, Standard-A receptacles are commonly found on computer USB ports, while Standard-B receptacles are typically on larger peripheral devices like printers and scanners. Mini and micro receptacles are often on smaller devices such as digital cameras and mobile phones. Most USB cables connecting a device to a computer have a Standard-A plug on one end and another type of plug on the other.
Connecting Devices with USB Cables
Apart from connector types, compliant USB cables are not proprietary and can connect devices to various platforms like Macintosh or Windows PCs. However, the software within the device may not be compatible with the host. It’s essential to note that some cables may appear similar but are not compliant with USB standards; these non-compliant connectors should lack the USB trident logo.
Versatile USB Cables
A standard USB cable comprises multiple wires, including a power supply wire for 5 volts, two twisted-pair data wires, and a ground wire. Under USB 2.0 specifications, the cable length is limited to five meters (approximately 16.4 feet) due to a cable delay specification of 26 nanoseconds. This limitation prevents excessive delays and reflections, ensuring that USB hosts receive timely responses to commands. To connect USB devices beyond this limit, solutions include using extender cables, self-powered hubs, up to five hubs in a chain, or building a bridge with a long-haul signaling protocol like Ethernet or RS-485.
In summary, USB cables are versatile connectors facilitating communication between various devices and hosts, adhering to standardized specifications for compatibility and performance.