How do HDMI cables send signals?
19 Jan 2012 21:05:09
Although they may look pretty simple, and they are straightforward to use, HDMI cables are actually quite sophisticated in the way that they work.
One of the biggest mysteries is how HDMI cables are able to send such high quality signals, and send both audio and video signals in the same cable. Let’s take a quick look at how they send signals…
Standard HDMI cables generally have around 19 pins, and it is from these pins that the signals begin their journeys. They travel from the pins through twisted pairs of copper cable until they reach their destination – the display device.
A total of three audio and three video channels travel through each cable, requiring two pins each. A further pair of pins is occupied by the TMDS clock, which helps devices to synchronise incoming data, and all of these pairs of pins are protected from signal interference by a shield wire.
The other pins on HDMI cables are used to carry other signals, such as the Consumer Electronics Channel (CEC), for example. In HDMI 1.4 cables, these pins may be used to carry the signal for the Ethernet Channel or the Audio Return Channel (ARC).