What is the USB CABLE?

USB CABLE

Universal Serial Bus (English: Universal Serial Bus, referred to as "USB")
When multimedia computers were first introduced, the transmission interfaces of external devices were different. For example, a printer can only connect to the LPT port, a modem can only connect to RS232, and a mouse and keyboard can only connect to PS/2. Complex interface systems, coupled with the need to install drivers and re-boot to use the restrictions, will inevitably cause users trouble. Therefore, it has become an unavoidable trend to create a unified external transfer interface that supports hot plugging.

Overview
USB was originally initiated by Intel and Microsoft. Its biggest feature is support for hot plug and plug and play. When the device is plugged in, the host enumerates to this device and loads the required driver, so it is far easier to use than the PCI and ISA bus.
USB speeds are much faster than traditional computer standard buses such as parallel ports (such as EPP and LPT) and serial interfaces (such as RS-232). The maximum transmission bandwidth of USB 1.1 in the original standard is 12Mbps, and the maximum transmission bandwidth of USB 2.0 is 480Mbps. The recently introduced USB 3.0 has been upgraded from 480Mbps to 5Gbps.
The design of the USB is asymmetric. It consists of a host controller and several devices that are connected in a tree form through hub devices. A controller can have up to 5 levels of Hub, including Hub, up to 128 devices can be connected, because in the design of the use of 7bit (bit) addressing field, two of the seventh power is equal to 128, most people say USB Connecting 127 refers to deducting a USB connector to the host when connecting (a device), and a computer can have multiple controllers at the same time. Unlike standards such as SPI-SCSI, USB hubs do not require terminators.
The USB can be connected to a mouse, keyboard, gamepad, joystick, scanner, digital camera, printer, hard disk, and network components. Multimedia peripherals such as digital cameras, USB, are already the default interface; as they greatly simplify the connection to computers, USB has gradually replaced parallel interfaces as the mainstream connection method for printers. In 2004, there were more than 100 million USB devices; by 2007, high-definition digital video peripherals were the only type of peripheral that USB could not address, because he needed higher transfer rates.

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