What is the overall size (non-screen size) of the access control videophone installed for each owner in the residential property?

Generally, it is about 4 to 5 inches, depending on the equipment parameters adopted by the access control manufacturer, and there are no fixed parameters.

According to the different image display, videophone can be divided into static image videophone and dynamic image videophone.

Static image The image displayed on the screen by videophone is still, and the existing analog phone system is used to transmit image signals and voice signals alternately, that is, you can't talk when transmitting images; It takes 5- 10 seconds to transmit the user's half-length still image.

Extended data

Videophone equipment can be connected to the public telephone network just like ordinary telephones. Dynamic image The image displayed by videophone is active, and the user can see the image of the other party smiling or talking.

Because of the large amount of information and wide frequency band, the video signal of dynamic videophone can't be transmitted directly on the subscriber line. It is necessary to digitize the original image signal into a digital image signal, and then band compression technology must be adopted.

Digital image signals are "compressed" to reduce the frequency band they occupy, so that they can be transmitted on subscriber lines. The signal of video phone is digital, so it needs to be transmitted in digital network.

Video phones can also be like recording phones, with video recording equipment, recording images and saving them. Still image videophone has been used in public telephone network, but dynamic image videophone has not been widely used because of its high cost.

Baidu encyclopedia-videophone