Interrupt transfers is a guarantee transmission frequency of the query. Then interrupt endpoint endpoint descriptor to report its query interval, the host will make sure to arrange a transfer within a range less than this time interval.
Talking about here is not actively interrupt an interrupt request sent by the device, but by the host guarantee to arrange a transfer within not more than a certain time interval. Interrupt transfer is usually used in the amount of data, but the more stringent requirements for the time device, such as a human interface device (HID) in the mouse, keyboard, trackball, and the like. Interrupt transfers can also be used continuously detect a state, when the condition is satisfied before using the bulk transfer large amounts of data to transmit.
In addition to the different strategies on the endpoints query, interrupt transmission and bulk transfer structure is basically the same, but there is no interruption in the transmission PING and NYET these Packs. Interrupt transfers using the interrupt Affairs
