Usb transaction translator and a bulk transaction method

A Universal Serial Bus (USB) IN bulk transaction method, comprising:

• sending an IN command to a transaction translator by a host;
• the transaction translator sending an IN token packet to a device according to the IN command, wherein the host has a USB version higher than the USB version of the device;
• the device responding to the transaction translator with data;
• storing the data from the device in at least two buffers alternately until all the buffers are full or a requested data length has been achieved;
• and
• the transaction translator sending the data stored in the buffers to the host when the host sends an IN acknowledge packet to the transaction translator.

A Universal Serial Bus (USB) OUT bulk transaction method, comprising:

• sending data to a transaction translator by a host;
• storing the data in at least two buffers alternately;
• the transaction translator sending the data stored in the buffers to a device;
• and
• when all the buffers are full, the transaction translator sending a negative acknowledge packet to the host to stop the host from sending the data;
• otherwise, the transaction translator sending an endpoint acknowledge packet to the host to begin receiving the data from the host.