| 摘要 |
Methods and systems for communicating information through a USB device using suspend/resume states are presented. A USB host stops transmitting Start-of-Frame (SOF) packets to a USB device, causing the USB device to enter a sleep/suspend state. The USB host then restarts the transmission of SOF packets to trigger the USB device back into a normal/resume state. The USB host repeats this process in a temporal pattern corresponding to a message, such that a circuit monitoring the USB device can determine the message.
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