... communication distance: more than 300 meters 2.max combination: 99 pcs 3.high clear voice 2.4GHz wireless audio intercom,supporting 99 pcs ... 100mw), Receive Sensitivity: <-1004. AFH technology, super anti-jamming capability5. Panel with 10 number button, a call key and two indicator ... coding process, press button 3 on master phone, press button 5 on extention phone, when in receiving code, press button ...