Electronic device and power source control method

An electronic device having a data transmission function using a network bus, comprising:

• a power source control circuit for controlling, independently of a physical layer and other layers, power applied to a protocol layer for controlling data transmission using the network bus;
• a user interface section for, when power-off of a device is instructed, inquiring whether to turn off power applied to the physical layer of the protocol layer;
• and
• a power source management section for, when power-off of the physical layer is instructed in accordance with the inquiry from said user interface section, causing said power source control circuit to turn off power applied to the protocol layer including the physical layer, and when keeping power applied to the physical layer is instructed, causing said power source control circuit to turn off power applied to the protocol layer except the physical layer.

An electronic device having a data transmission function using a network bus, comprising:

• a power source control circuit for controlling, independently of a physical layer and other layers, power applied to a protocol layer for controlling data transmission using the network bus;
• a determination section for determining a connection arrangement of said device on a network formed by the network bus;
• a user interface section for inquiring whether to turn off power applied to the physical layer of the protocol layer;
• a first power source management section for, when power-off of a device is instructed, determining from a determination result of said determination section whether said device acts as a role of mediation in data transmission between other devices, when said device is determined not to act as a role of mediation in data transmission, causing said power source control circuit to turn off power applied to the protocol layer including the physical layer, and when said device is determined to act as a role of mediation in data transmission, causing said user interface section to inquire whether to turn off power applied to the physical layer of the protocol layer;
• and
• a second power source management section for, when power-off of the physical layer is instructed in accordance with the inquiry from said user interface section, causing said power source control circuit to turn off power applied to the protocol layer including the physical layer, and when keeping power applied to the physical layer is instructed, causing said power source control circuit to turn off power applied to the protocol layer except the physical layer.

A power source control method for an electronic device having a data transmission function using a network bus, comprising:

• determining a connection arrangement of the device on a network formed by the network bus when power-off of the device is instructed;
• determining from a determination result whether the device acts as a role of mediation in data transmission between other devices;
• and
• when the device is determined to act as a role of mediation in data transmission, turning off power applied to a protocol layer except a physical layer of the protocol layer formed to control data transmission using the network bus, and when the device is determined not to act as a role of mediation in data transmission, turning off power applied to the protocol layer including the physical layer.

A control method for an electronic device having a data transmission function using a network bus, comprising:

• determining a connection arrangement of the device on a network formed by the network bus;
• when power-off of the device is instructed, determining from a determination result whether the device acts as a role of mediation in data transmission between other devices, when the device is determined not to act as a role of mediation in data transmission, turning off power applied to a protocol layer including a physical layer, and when the device is determined to act as a role of mediation in data transmission, inquiring whether to turn off power applied to the physical layer of the protocol layer;
• and
• when power-off of the physical layer is instructed in accordance with the inquiry, turning off power applied to the protocol layer including the physical layer, and when keeping power applied to the physical layer is instructed, turning off power applied to the protocol layer except the physical layer.