A control method of an air conditioner system comprising a plurality of units, the method comprising: transmitting (S710), by a first unit among a plurality of units belonging to a particular group, a wireless signal auto tuning command to a second unit; measuring, by the second unit, reception sensitivity and a transmission and reception success rate, by wirelessly communicating with units belonging to the particular group while reducing signal strength from default signal strength; when the reception sensitivity and the transmission and reception success rate, which are measured by the second unit, satisfy the predetermined standard, determining, by the second unit, that signal strength corresponding to a level right before a level satisfying a predetermined standard is signal strength for use; and transmitting, by the second unit, information related to the signal strength for use to the first unit; the method further comprising: transmitting, by the first unit, the wireless signal auto tuning command to a third unit belonging to the particular group; measuring, by the third unit, the reception sensitivity and the transmission and reception success rate, by wirelessly communicating with units belonging to the particular group while reducing signal strength from the default signal strength by one level at a time; when the reception sensitivity and the transmission and reception success rate, which are measured by the third unit, satisfy a predetermined standard, determining, by the third unit, that signal strength corresponding to a level right before a level satisfying the predetermined standard is signal strength for use; and transmitting, by the third unit, information related to the signal strength for use to the first unit. transmitting (S710), by a first unit among a plurality of units belonging to a particular group, a wireless signal auto tuning command to a second unit; measuring, by the second unit, reception sensitivity and a transmission and reception success rate, by wirelessly communicating with units belonging to the particular group while reducing signal strength from default signal strength; when the reception sensitivity and the transmission and reception success rate, which are measured by the second unit, satisfy the predetermined standard, determining, by the second unit, that signal strength corresponding to a level right before a level satisfying a predetermined standard is signal strength for use; and transmitting, by the second unit, information related to the signal strength for use to the first unit; transmitting, by the first unit, the wireless signal auto tuning command to a third unit belonging to the particular group; measuring, by the third unit, the reception sensitivity and the transmission and reception success rate, by wirelessly communicating with units belonging to the particular group while reducing signal strength from the default signal strength by one level at a time; when the reception sensitivity and the transmission and reception success rate, which are measured by the third unit, satisfy a predetermined standard, determining, by the third unit, that signal strength corresponding to a level right before a level satisfying the predetermined standard is signal strength for use; and transmitting, by the third unit, information related to the signal strength for use to the first unit. <EOS>