Control transmission: control transfer is a two-way transfer, usually small amount of data. USB system software used mainly to query, configure, and send generic commands to USB device. The delivery can include 8, 16, 32, and 64 bytes of data, depending on the USB device and transfer rate. Transmission is typically used to control the main computers and USB peripherals between transmission between endpoint 0.
Synchronization Isochronous £ transmission: synchronous transport provided determines the bandwidth and time. It is used in the flow of time and have strong fault-tolerance data, or used to require a constant data transfer rate real-time applications. Performs an immediate call for example VoIP application, use synchronous transfer mode is a good choice. Synchronization data requirements to determine the bandwidth and determine the maximum number of transmit. For synchronous transmission, data transmission rates than perfect accuracy and data integrity is more important than others.
Interrupt Interrupt £ transmission: interrupt transmission is mainly used for regular queries the device interrupt data transfers. Device structure for the endpoint mode determines its frequency from between 1ms~255ms. This transmission typically used in small, decentralized and unpredictable data transfer. Keyboard, joystick and mouse fall into this category. Interrupting transmission is unidirectional and only entered for the Host.
Large Bulk human transmission: mainly used in data transmission and reception of data in huge quantities, and no bandwidth and time requirements of the case, requiring guaranteed delivery. Printers and scanners are of this type. This type of equipment suitable for transmission is slow and much delayed transmission, can wait until after the completion of all other types of data transmission to transmit and receive data.
Disadvantages of USB drive write speed slower USB1.0 0.5MB~2MB USB2.0 2.0MB~4.0MB USB3.0 3.0MB~6.0MB