... phone,3.5 inch display screen,touch button2,Video intercom,unlocking,monitor functions3,Intercome between inner monitors4,Infared night ... digital frequency hopping and encryption technology, (2) Hands-free intercom,clear voice.(3) calling button for begin to work, ... power.(4) 83 channels available to ensure the stable intercom(5) perfect automatic frequency adjusting technique,super erroe correction ...