how commax video door phone send and receive audio with one wire ?

[mf1364]

Hi every body
Does any body have notice to commax video door phones ? ( I have opened a set of Commax video door phone indoor panel and outdoor panel) there are 4 wires between indoor panel and outdoor panel the red one is for audio between indoor panel and outdoor panel the blue is grand and the yellow is positive 12V and the white is camera signal. now my question is how those indoor and outdoor video door phone send and receive audio between each other just with one wire ? If some body have circuit schematic or can explain about Commax audio circuit please help me

 

[tpetar]

Hi every body
Does any body have notice to commax video door phones ? ( I have opened a set of Commax video door phone indoor panel and outdoor panel) there are 4 wires between indoor panel and outdoor panel the red one is for audio between indoor panel and outdoor panel the blue is grand and the yellow is positive 12V and the white is camera signal. now my question is how those indoor and outdoor video door phone send and receive audio between each other just with one wire ? If some body have circuit schematic or can explain about Commax audio circuit please help me

Can you imagine ADSL broadband over only two tiny copper wires (Internet 34Mb/s, IPTV, PSTN) all in the same time.



Broadband
https://en.wikipedia.org/wiki/Broadband

The term broadband refers to the wide bandwidth characteristics of a transmission medium and its ability to transport multiple signals and traffic types simultaneously. The medium can be coax, optical fiber, twisted pair or wireless. In contrast, baseband describes a communication system in which information is transported across a single channel



Best regards,
Peter

;-)

 

[betwixt]

Without ever seeing one I assume it works in the same way as a telephone connection. You know how much audio you are adding at 'your' end so if you subtract it from the amount on the wire, anything remaining must come from the other end.

Brian.

 

[mf1364]

Thanks guys but I want a circuit schematic and strong analyzes, because I want to use in my intercom circuit