CRT: 4 "flat picture tube (CRT) Definition: 420TV Line temperature: -30 ℃ ~ +55 ℃ Humidity: 45% ~ 95% of the video transmission: coaxial cable 75 European imaging time: about 60 seconds, or re- Press monitor key to shutdown voltage: DC12V Function: video intercom, surveillance, remote unlocking number calling sound level: 70dB Dimension: 180 * 215 * 50mm 
 Function operation 
 (A) the use outside the host 
 1, the visitors pressed the doorbell button, the door of room can hear the sweet tone. 
 2, through the microphone and the room can make a call. 
 3, with infrared illumination by itself, even at night, no lighting in the outdoor installation, but also shows visitors a clear picture. 
 (B) the use of indoor unit 
 1, the host received the call. 
 A, the indoor electronic ringing extension rings, and show visitors the image. 
 B, if the owner intends to reception, and visitors can pick up the call, press the unlock button to open the electric lock. 
 C, if the owner did not want to reception, they do not pick up, this time to look at visitors, not make visitors aware of the indoor movement. 
 2, can be reproduced by the image display monitor button, hang up automatically into the waiting state. 
 3, the interior to hear the call if not pick up the indoor unit automatically after 60 seconds into the waiting state. 
 4, by monitoring key, indoor outdoor extension to the host to monitor the situation. 
 5, adjust the "contrast" button, you can change the image black and white contrast. 
 6, hook and press the "unlock" button to open the electric lock.