(03-04-2016 22:00)Comandante писал(а):  Ни к самому правилу передачи данных, ни к его интерфейсу - это не имеет никакого отношения.

_http://www.edn.com/design/consumer/4376143/Fundamentals-of-USB-Audio
" There are four sorts of IN and OUT-transfers in USB: Bulk, Isochronous, Interrupt, and Control transfers.

A bulk transfer is used to reliably transfer data between host and device. All USB transfers carry a CRC (checksum) that indicates whether an error has occurred. On a bulk transfer, the receiver of the data has to verify the CRC. If the CRC is correct the transfer is acknowledged, and the data is assumed to have been transferred error-free. If the CRC is not correct, the transfer is not acknowledged and will be retried.

If the device is not ready to accept data it can send a negative-acknowledgment, NAK, which will cause the host to retry the transfer. Bulk transfers are not considered time criticial, and are scheduled around the time critical transfers discussed below.

Isochronous transfers are used to transfer data in real-time between host and device. When an isochronous endpoint is set up by the host, the host allocates a specific amount of bandwidth to the isochronous endpoint, and it regularly performs an IN- or OUT-transfer on that endpoint. For example, the host may OUT 1 KByte of data every 125 us to the device. Since a fixed and limited amount of bandwidth has been allocated, there is no time to resend data if anything goes wrong. The data has a CRC as normal, but if the receiving side detects an error there is no resend mechanism.

USB Audio uses isochronous, interrupt and control transfers. All audio data is transferred over isochronous transfers; interrupt transfers are used to relay information regarding the availability of audio clocks; control transfers are used used to set volume, request sample rates, etc."