摘要 |
A USB device is coupled to a first USB communication line and a second USB communication line. Separate first and second paths are created between an external device and a controller in the USB device, with both paths including the first and second USB communication lines. The USB device detects whether a USB connection exists over the first and second USB communication lines. If a USB connection exists over the first and second USB communication lines, USB communication is routed via the first path. Otherwise, testing communication is routed via the second path. The external device can be either a USB host or a testing unit.
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