As our professor said, that our class room is a transmission system. The meaning of transmission is the “action or process of transmitting something or the state of being transmitted”(wiki) or “a program or signal that is broadcast or sent out”(wiki). so what mean is transmission system. here is a image that describe it
basically is just to send out the message and receive, and the process is a decoding process. Also, there are many different transmission relate to our life, such as mechanic.Beside this, we also talked about package switching. the mean may seems complicated “a mode of data transmission in which a message is broken into a number of parts that are sent independently, over whatever route is optimum for each packet, and reassembled at the destination.”(wiki) basically is just classification and group up send to the destination. and here is a brief video that describe it.