Best HDMI Cable Manufacturer in China since 2008

A complete introduction of an HDMI Cable

It will consist of following contents

1、 What is an HDMI Cable

High Definition Multimedia Interface, abbreviated as HDMI, is the first and only digital interface that integrates uncompressed high-definition video, multi-channel audio, and intelligent formats with command data in a single digital interface.

2、 Founder of an HDMI Cable

In April 2002, seven companies, including Hitachi, Panasonic, Philips, Crystal Image, Sony, Thomson, and Toshiba, established the HDMI organization and began developing new standards specifically for digital video/audio transmission.

3、 HDMI SPEC and HDMI CTS

The HDMI SPEC (Specification) mainly defines the architecture of the entire HDMI system (including the overall requirements for application methods, physical characteristics such as size, electrical characteristics such as voltage resistance, software characteristics such as communication protocols and encoding), and some parts require reference to other specifications, such as video and audio encoding methods in communication

HDMI SPEC：High-Definition Multimedia Interface Specification

HDMI CTS (Compatibility Testing) is a specification document that specifically specifies the measurement method, meaning that CTS clearly defines the equipment and methods used for measurement based on the specifications specified in SPEC, without involving other parts of the specification

HDMI CTS：High-Definition Multimedia Interface Compliance Test Specification

4、 Applications of an HDMI Cable

(1) Application on DTV, DVD, set-top box, A/V receiver

(2) Application on PC

(3) Application on Multimedia

5、 Testing items for an HDMI Cable

Physical dimensions checking; Internal delay time difference; Delay time difference between pairs; Remote crosstalk; Attenuation; Characteristic impedance.

6, Functions of pins in an HDMI Cable

The PINs of an HDMI Cable have a total of 19 PINs, which can be roughly divided into two groups. The yellow part above is the high-frequency part, and the blue part below is the low-frequency part. The high-frequency part is mainly responsible for transmitting image and sound data, divided into four pairs: red, blue, green, and clock signal (CLOCK). Due to the differential transmission of high-frequency signals, each color has three PIN pins, such as TMDS Data2 transmitting red signals, Among them, 2+is the positive signal of differential, 2- is the negative signal of differential, 2 shield is the ground of this pair, and the other pairs are the same. In addition, the low-frequency part is responsible for communication between source (DVD) and display (TV) during use, which will be explained in detail later. The structure of the entire HDMI product line can be said to be responsible for communication between source (DVD) and display (TV) by the low-frequency pin, After confirming that there is no problem between the source (DVD) and display (TV), the source (DVD) will send red, blue, and green images and sounds respectively from the high-frequency feet.

The TMDS Data0 in the high-frequency part of the PIN pin of an HDMI cable transmits blue and data packets, TMDS Data1 transmits green and sound, TMDS Data2 transmits red data and sound, and clock is responsible for clock signals.

FunctionS of the PINs of the low-frequency part in an HDMI Cable are as follows:

(1) CEC: Consumer Electronics Control is a consumer electronic control that allows users to control all electronic devices connected through HDMI through a remote control. For example, a DVD is connected to an HDMI amplifier and then connected to an HDMI TV. If there is CEC, users only need to use the DVD’s remote control to power on, and the three devices will power on together without the need to power on three devices separately, increasing the convenience of use.

(2) SCL, SDA: These two PINs are used for communication between source (DVD) and display (TV). There is a memory inside the TV that stores information about the resolution supported by the TV, such as 720P or 1080P. If the source (DVD) does not know the current TV resolution supported by the connected TV, the source (DVD) does not know what resolution signal to broadcast, Therefore, at the beginning, the source (DVD) will read the resolution supported by the TV through these two pins. Only when the source (DVD) knows about it, the source (DVD) will send an image that matches the TV resolution. SCL is the clock (CLOCK) pin, and SDA is the data pin

(3) +5V: This pin of HDMI cable is provided by the source (DVD) with a voltage of+5V to the display (TV) terminal. Its main purpose is to avoid the source (DVD) from reading the memory of the TV through the SCL and SDA pins when the display (TV) is not turned on or is not plugged in at all when the source (DVD) is turned on. Therefore, the source (DVD) is used to supply power, and this pin is usually not used

(4) GND: This PIN is a+5V ground wire

(5) HPD: Hot plug detection is a high potential (approximately+5V) pin on the display (TV) end. When HDMI cable is used to connect the source (DVD) and display (TV), the source (DVD) will detect whether the pin is high or low potential to confirm whether it is connected to the TV or unplugged, and decide whether to send or not to send a signal.