... 300 meters in open landOperationuPower onConnect the plug to electricity.uStandby statusHand up status: the intercom ... : Press the ID number of the intercom you want to call, then press CALL button, RED light ... Phone, press number 5 on Extention Phone to receive code, which means in coding process, press button ... from 0~99, press the ID number which you want to set, then confirm by pressing CALL key, ...