Method of handling transmission in data transmission system

1. A method of handling transmission for a host in a data transmission system, the method comprising:

establishing a connection with a device of the data transmission system via a first frequency;

receiving a negotiating information from the device; and

re-establishing the connection with the device via a second frequency when the negotiating information reveals that the second frequency is available for the host to communicate with the device;

wherein the second frequency is lower than the first frequency;

wherein a data transmission frequency between the device and the host is changed from the first frequency to the second frequency when interference signals are detected, the second frequency is a user-defined frequency different than the first frequency defined by an USB standard, and the interference signals are generated by a data transmission with the first frequency.

2. The method of claim 1 , wherein the step of receiving the negotiating information from the device comprises:

detecting interference signals around the first frequency; and

notifying the device to transmit the negotiating information when a degree of the interference signals is greater than a threshold.

3. The method of claim 1 , wherein the data transmission system is a universal serial bus (USB) system.

4. The method of claim 3 , wherein the step of receiving the negotiating information from the device is performed during a training process of the USB system.

5. The method of claim 1 , wherein the step of receiving the negotiating information from the device is performed after data is transmitted in the data transmission system.

6. The method of claim 1 , further comprising:

receiving another negotiating information related to a third frequency from the device when the second frequency is not available for the host to communicate with the device.

7. A method of handling transmission for a device in a data transmission system, the method comprising:

establishing a connection with a host of the data transmission system via a first frequency;

transmitting a negotiating information to the host; and

allowing the host to re-establish the connection via a second frequency when the host is required to re-establish the connection via the second frequency according to the negotiating information;

wherein the second frequency is lower than the first frequency;

wherein a data transmission frequency between the device and the host is changed from the first frequency to the second frequency when interference signals are detected, the second frequency is a user-defined frequency different than the first frequency defined by an USB standard, and the interference signals are generated by a data transmission with the first frequency.

8. The method of claim 7 , wherein the step of transmitting the negotiating information to the host comprises:

receiving a notification from the host when a degree of interference signals detected by the host is greater than a threshold.

9. The method of claim 7 , wherein the data transmission system is a universal serial bus (USB) system.

10. The method of claim 9 , wherein the step of transmitting the negotiating information to the host is performed during a training process of the USB system.

11. The method of claim 7 , wherein the step of transmitting the negotiating information to the host is performed after data is transmitted in the data transmission system.

12. The method of claim 7 , further comprising:

receiving a notification indicating that the second frequency is not available for the host to communicate with the device;

transmitting another negotiating information related to a third frequency to the host.