Master and slave, and identification number setting apparatus

An identification number setting apparatus including a master device and a plurality of slave devices connected to a bus according to a multi-drop communication scheme,

• wherein when the master device transmits an identification number setting command packet to the plurality of slave devices, a slave device in which an identification number is first set sets an identification number according to a first setting operation and transmits the set identification number to the bus, and
• the other remaining slave devices, excluding the slave device which has first transmitted the identification number, among the plurality of slave devices, each set a value, which does not overlap identification numbers of the other slave devices previously received through the bus, as its identification number according to second setting operations sequentially input to the other remaining slave devices, and transmit the set identification number to the bus.