Switching method of USB switch element for in-vehicle host system

A switching method between a device mode and a host mode of a universal serial bus (USB) switch element for an in-vehicle host system, comprising following steps:

• an in-vehicle host device initializes a switch device connected to the in-vehicle host device;
• the in-vehicle host device transmits a switching command to the switch device via a host port;
• the switch device receives the switching command;
• and
• according to the switching command, a hub controller included in a hub device located in the switch device controls the switch element located in the switch device to switch from a device mode to a host mode, so that one of a plurality of mobile terminals connected to the switch element is in the host mode, or alternatively the switch element is controlled to switch from the host mode to the device mode, so that a plurality of peripheral devices connected to the hub device located in the switch device are in the device mode;
• wherein the device mode is a state in which the in-vehicle host device controls the peripheral devices through the hub device;
• the host mode is a state in which one of the mobile terminals controls the in-vehicle host device, and the hub device, in response to the switch device is in the host mode in which the in-vehicle device is under control of the one of the mobile terminals, disables the peripheral devices;
• wherein the mobile terminals comprise a first mobile terminal and a second mobile terminal, and the hub controller, in response to that the first mobile terminal and the second mobile terminal are connected to the switch device, controls the switch element to switch from the first mobile terminal in the host mode to the second mobile terminal in the host mode according to the switching command.