Patent ID: 8063745

Claim:
An air conditioner in which one control portion and a plurality of indoor units are connected to each other through a communication line and running is controlled by conducting communication between said control portion and said plurality of indoor units based on a communication address corresponding to each of said plurality of indoor units, wherein each of said plurality of indoor units includes a transmitting portion and a receiving portion, said receiving portion receiving detection commands that each requests a different one of digits of a unique indoor unit identification number from said control portion through said communication line, said transmitting portion transmitting a response including the identification number digit that corresponds to the detection command through said communication line, said control portion includes: an identification number detection portion which repeatedly transmits, in a predetermined order said detection commands to said plurality of indoor units, a position of said identification number digits being changed for the repeatedly transmitted detection commands, and detects said identification number; when no response to a first detection commands of said detection commands is received, said identification number detection portion simultaneously transmits to said plurality if indoor units a second detection command of said detection commands that immediately precedes said first detection command of said detection commands based on said predetermined order; and an address setting portion which imparts said communication address to one of said plurality of indoor units having said identification number detected by said identification number detection portion.