Systems and methods for providing device-to-device handshaking through a power supply signal
First Claim
1. A method for restricting supply of power between a first device and a second device, the method comprising:
- receiving power at the first device, the first device comprising handshaking circuitry operative to selectively provide a power supply signal including a first characteristic or a second characteristic to the second device depending on whether a series of predetermined current pulses are detected on the power supply signal;
monitoring, at the handshaking circuitry, the power supply signal to determine whether the series of predetermined current pulses are being received;
providing the power supply signal having the first characteristic to the second device when the series of predetermined current pulses are not being received on the power supply signal; and
providing the power supply signal having the second characteristic to the second device while the series of predetermined current pulses are being received on the power supply signal.
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Accused Products
Abstract
Handshaking circuits are provided in a communications cable and in a device operable to be mated with the communications cable. Before a device can utilize the power supply signal of such a communications channel, the two handshaking circuits must sufficiently identify one another over a power supply signal with a decreased voltage. The decreased voltage allows for a cable plug to be provided with a safe, protected power that cannot cause harm to a human. The decreased voltage also reduces the chance that a device can receive a primary power supply signal from the cable before the device sufficiently identifies itself. Accordingly, a laptop may be connected to a portable music player, but the voltage of the power supply signal provided by the laptop to the cable may be decreased on-cable until the handshaking circuit of the portable music player sufficiently performs a handshaking operation with a on-cable handshaking circuit.
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Citations
20 Claims
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1. A method for restricting supply of power between a first device and a second device, the method comprising:
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receiving power at the first device, the first device comprising handshaking circuitry operative to selectively provide a power supply signal including a first characteristic or a second characteristic to the second device depending on whether a series of predetermined current pulses are detected on the power supply signal; monitoring, at the handshaking circuitry, the power supply signal to determine whether the series of predetermined current pulses are being received; providing the power supply signal having the first characteristic to the second device when the series of predetermined current pulses are not being received on the power supply signal; and providing the power supply signal having the second characteristic to the second device while the series of predetermined current pulses are being received on the power supply signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for using a power supply signal between a first device and a second device, the method comprising:
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receiving the power supply signal with a first handshaking circuitry of the first device; changing a first characteristic of the power supply signal, wherein the first characteristic is changed by the first handshaking circuitry; recognizing the changed first characteristic with a second handshaking circuitry of the second device; introducing current spikes into the power supply signal in response to recognizing the changed first characteristic, wherein the current spikes are introduced by the second handshaking circuitry; recognizing the current spikes with the first handshaking circuitry; and altering a second characteristic of the power supply signal in response to recognizing the current spikes, wherein the second characteristic is altered by the first handshaking circuitry; wherein the first device is a cable that is coupled to the second device, and wherein the first handshaking circuitry is located within the cable; wherein the cable comprises one or more plugs; and wherein at least one of the plugs is a Universal Serial Bus plug. - View Dependent Claims (12)
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13. An electronic device comprising:
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electrical contacts for interfacing with another device; handshaking circuitry electrically coupled to at least one of the electrical contacts, the handshaking circuitry operative to; selectively provide a power supply signal including a first characteristic or a second characteristic to the other device via the at least one of the electrical contacts depending on whether a series of predetermined current pulses are monitored on the power supply signal; monitor the at least one electrical contact to determine whether a series of predetermined current pulses are being received on the power supply signal; wherein the power supply signal having the first characteristic is provided to the other device when the series of predetermined current pulses are not monitored as being received on the power supply signal; and wherein the power supply signal having the second characteristic is provided to the other device while the series of predetermined current pulses are monitored as being received on the power supply signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification