... time, inside buy a variety of chord tones, pictures, video and other functions; the touch button design, durable, wear- ... machine free form 1 to 1, 1 to 2,2 in 1, 2 to 2, 2 to 4, to meet the needs of ... automatically open, there is no need to go to the door to open, if the room no answer, indoor machine ... mode, by monitoring key, can monitor the external environment. 2 wire video doorbell for villa