Look at the attachment.There's no data in and data out.
Well... still no.Look at the attachment.
I think what is being said here is that the in out control is a software solution.(traffic control scheme)Well... still no.
There are no data in and data out wires. Both D+ and D- form a bidirectional differential signal data link between the host and peripheral, which the direction is protocol controlled by the host.
Please refer to USB standard.