... intercom will sound 15 “Du…”, and simultaneously time 1 minute.Remark:when in the standby status and ID ... process, press button 3 on master phone, press button 5 on extention phone, when in receiving code, press ... button 4 on the master phone, press button 5 on extention phone.ID setting, Coding, Give code, ... to setting status. Wholesale 2.4GHz wireless digital audio doorbell for 4 apartments