功能说明: (4.5”免提黑白可视门铃)·带1路视频信号输入·视频信号·亮度、对比度调节功能·视频/音频输出功能·带对讲或不对讲功能·摄像头解晰度高，功耗小·高灵敏度感光芯片·摄像头视频/音频输出·摄像头可做多1) 4" flat B/W CRT display, with high resolution and high contrast ratio2) The outdoor station adopts CCD camera to gain clear image3) With night vision4) Talk with the visitor5) Unlock the electronic controlled door lock6) Monitor the situation out of the door7) Handfree talking with the visitor