Three-way handshaking method and computer readable media

A computer readable media, storing a code, wherein the following steps are executed when the code is executed by a processor:

• controlling a first port which is in a first specific mode to send a first specific signal to a second port, and controlling the first port to enter into a second specific mode;
• when the first port receives a second specific signal, determining the second port is in the second specific mode, and controlling the first port to send a third specific signal to the second port;
• and
• controlling the first port to enter into the third specific mode when determining the second port is in a third specific mode.