Systems and methods for providing device-to-device handshaking through a power supply signal

A method for authenticating an accessory device with a main device, the method comprising:

• transmitting a power supply signal from the accessory device to the main device;
• receiving an initiating handshake signal from the main device, the initiating handshake signal corresponding to a request for a response handshake signal from the accessory device;
• transmitting the response handshake signal via the power supply signal;
• and
• authenticating with the main device according to the response handshake signal.

A computing device, comprising:

• a processor;
• a memory;
• and
• a handshake circuit, configured to:
• receive a power supply signal from an accessory device and compare the power supply signal to one or more threshold values;
• send an initiating handshake signal to the accessory device based on a result of comparing the power supply signal to the one or more threshold values;
• and
• receive a response handshake signal from the accessory device for authenticating the accessory device.

A first device, including a handshake circuit configured to:

• transmit a power supply signal to a second device;
• receive a handshake request from the second device to authenticate the first device;
• transmit a handshake signal via the power supply signal to the second device;
• and
• authenticate with the second device according to the handshake signal.