... always in the receiving signal status, light indicator twinkles 4 seconds a time.uCall:A: Press the ID ... Receive code operation, Should press number button 3 and 4 on the Master Phone, press number 5 on Extention ... extention phone, when in receiving code, press button 4 on the master phone, press button 5 on extention ... to setting status. Wholesale 2.4GHz wireless digital audio doorbell for 4 apartments