Method for synchronously implementing media switch in gateways used for fax over IP network

A method for synchronously implementing media switch in gateways used for IP FAX between two fax machines, comprising:

• generating a fax signal by the fax machine which is firstly activated by a fax event;
• identifying that the fax event occurred after a media gateway, which is communicating with the fax machine firstly activated, receives the fax signal;
• sending a message for notification of fax event to the other media gateway of the fax event, wherein the message for notification of fax event is carried by an Application-defined RTCP packet;
• implementing a media switch in the media gateway into fax mode;
• and
• implementing a media switch in the other media gateway of the fax event into fax mode after receiving the message for notification of fax event;
• the method further comprising:
• the step of sending the fax signal to the media gateway if the communicated fax machine is firstly activated to generate the fax signal, and
• the step of sending a CED signal to the media gateway at a fax receiving side if the fax machine is firstly activated at the fax receiving side.