The data throughput, or rate of transfer of application data, between a device and host is lss than the bus speed and isn’t always predictable. Some of the  transmitted bits identify, synchronize, and error-check the data, and the throughput also varies with the transfer type and how busy the bus is.For time-sensitive data, USB supports transfer types that have a guaranteed rate or guaranteed maximum latency. Isochronous transfers have a guaranteed rate,where the host can request a specific number of bytes to transfer at defined intervals. The intervals can be as short as 1 ms at full speed or 125 μs at high speed and SuperSpeed.

Isochronous transfers have no error correcting, however.Interrupt transfers have error correcting and guaranteed maximum latency. The device specifies a maximum interval, and when a driver has requested a data transfer, the host allows no more than the specified interval, or maximum latency, to elapse between transfer attempts. The requested maximum interval can have a range of 10–255 ms at low speed, 1–255 ms at full speed, and 125 μs to 4.096 s at high speed and SuperSpeed.