The USB interface has 4 cables, the USB interface is laid flat, in order is 1, 2, 3, 4 contacts, the corresponding power cable, data cable, data cable, ground, that is, red, green, white, black, details are as follows:
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1, VBUS (4.75-5.25V), power cord, red cable.
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2, data-, data transmission line, green line.
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3, data+, data transmission line, white line.
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4. gnd, ground wire, black wire.
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Extended data
USB supports four basic data transfer modes: control transfer, isochronous transfer, interrupt transfer, and data block transfer. Each transmission mode, applied to a terminal with the same name, has different properties.
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1. Control transmission type: Support the transmission of control, status, configuration and other information between peripherals and hosts, providing a control channel between peripherals and hosts. Each peripheral supports a control transfer type so that configuration and command\/status information can be transmitted between the host and the peripheral.
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2, isochronous (lsochronous) transmission type (or synchronous transmission) : support periodic, limited delay and bandwidth and data transmission rate unchanged between the peripheral and the host data transmission. This type is error-free, so it cannot guarantee correct data transmission, and supports data transmission like computer-telephone integrated system (CTI) and audio system with the host.
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3, interrupt transmission type: Support such as gamepad, mouse and keyboard input devices, the amount of data transmission between these devices and the host is small, no periodicity, but sensitive to response time, require immediate response.
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4, data block (Bulk) transmission type: support printers, scanners, digital cameras and other peripherals, the amount of data transmitted between these peripherals and the host is large, USB in the case of meeting the bandwidth for this type of data transmission.
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USB uses the block bandwidth allocation scheme. If a peripheral exceeds the current bandwidth allocation or potential requirements, the device cannot be accessed. Terminals of the synchronous and interrupt transmission types retain bandwidth and ensure that data is transmitted at a certain rate. The central and control terminal transmits transmission data at the best available bandwidth.