HDMI cables have become integral to modern life. Innumerable consumer electronics use HDMI cables, including televisions, gaming consoles, digital cameras, soundbars, computers, phones, etc. Hence, it is imperative for many to understand HDMI cables, their types, and connections.
HDMI cables transfer video, audio, and data among compatible devices. There are more than 6 types of HDMI cables using 5 kinds of connections. However, only 3 connections are prevalent. Additionally, the older types of HDMI cables are becoming almost obsolete now.
HDMI cables have been around for less than 20 years, but they have evolved swifter than USBs. The latest HDMI cables support 8K video and have an Ethernet channel to use an internet or Wi-Fi network. Read on to explore the ultimate guide to HDMI cables, their types, and connections.
Also read: 4 Common Bad HDMI Cable Symptoms (with Fixes)
What Is an HDMI Cable?
HDMI is a distinct standard for digital data transfer. Thus, an HDMI cable has no similarities with analog interfaces, such as VGA, RCA, etc. Additionally, the protocols used by HDMI cables are not the same as how USBs and other such ports function.
Until the advent of digital connections, the most popular analog interfaces were VGA (for video) and RCA (for audio). VGA was exclusively for video. RCA interfaces with 3 cables support a stereo audio output with composite video.
DVI or Digital Visual Interface replaced the VGA cables. However, a DVI cable was still confined to only video. And RCA cables or others were a multi-port connection to transfer audiovisual content from one device to another.
Hence, we didn’t really have a single-port solution to transfer digital video and audio without any compression and quality loss. Any setup facilitating the transfer of composite video with audio would essentially compress the data, thus causing a significant loss in quality.
Composite video and audio cables didn’t support 1080p or even 720p in the cases of the earlier variants. Also, many cables didn’t support balanced audio transfer or output. All of that changed with HDMI cables.
An HDMI cable is a High-Definition Multimedia Interface capable of transferring video and audio. Unlike analog interfaces, an HDMI cable transfers uncompressed video and audio digitally without any loss of quality. Also, the newer HDMI cables are internet-enabled.
Now, you don’t need multiple cables to connect a television or any HDMI-enabled display to a source or intermediary device to have both video and audio. Plus, you can watch uncompressed videos.
Also read: Does HDMI Support 4K? All You Need to Know
How an HDMI Cable Works
An HDMI cable uses a proprietary standard that is unique compared to the protocols used by other interfaces. Before I explain how an HDMI cable works, here are a few terms you should know:
- TMDS: Transition-Minimized Differential Signaling.
- CEC: Consumer Electronics Control.
- DDC: Display Data Channel.
- SCL: Serial Clock for DDC.
- SDA: Serial Data Line.
- HPD: Hot Plug Detection.
- HEC: HDMI Ethernet Connection.
- ARC: Audio Return Channel.
- HEAC: HDMI Ethernet and Audio Channel.
- FRL: Fixed Rate Line.
The protocol used by HDMI cables covers several pre-existing standards, like EIA/CEA-861, LPCM, VESA EDID, etc. In addition, HDMI cables support various audio standards, such as Dolby. Furthermore, HDMI cables facilitate the highest video resolution, subject to their bandwidths.
These standards apply to all HDMI cables, and I’ll discuss bandwidths while talking about the specific types. But what’s important for a user is the manner in which an HDMI cable transfers data or the video and audio digital signals; this is essentially based on TMDS.
Transition-Minimized Differential Signaling
Transition-Minimized Differential Signaling (TMDS) is a fascinating and complex way to process digital signals.
The primary objective is reducing signal loss, which is otherwise inevitable. Most digital signals suffer from enormous loss with increasing distance and time. This loss and other interferences often referred to as noise compromise the quality of audiovisual content.
Thus, HDMI cables use Transition-Minimized Differential Signaling (TMDS) to ensure that the output quality matches or is as close to the input feed as possible.
To achieve this, HDMI cables use a few processes, including:
- Differential Signaling
- Twisted Pairs
- Low-Voltage Differential Signaling
- DC Balancing
- Transition Minimization
The technical jargon aside, here’s how HDMI cables handle digital signals:
- An HDMI cable has multiple channels for digital signals. A single HDMI cable uses 4 pairs of wires: 3 for data and 1 for the clock.
- Every pair has twisted wires to reduce interference and signal loss. The traditional coaxial wires are inefficient in comparison with twisted pairs.
- One of the two wires in every twisted pair carries a reverse digital signal. The other wire carries the regular or positive signal.
- The positive and negative digital signals are encoded to mitigate any significant loss of quality. However, HDMI cables don’t compress any video or audio.
- The positive and negative digital signals are then decoded and tallied to eliminate interferences. The erstwhile approach is comparing a positive signal to the ground.
- Every twisted pair has a shield to protect the positive and negative signals from interference. Thus, an HDMI cable has 4 shields for as many pairs.
- One of these twisted pairs carrying the clock and its reverse has a shield, too. So, all pairs are shielded from electrical and electromagnetic interference.
Therefore, an HDMI cable uses 12 wires to carry the digital signals from a source to an output or display. There are 7 more wires to talk about while discussing the types and connections of HDMI cables.
Additionally, the digital signals are encoded. Plus, the positive and negative or reverse signals are compared and processed to retain the original quality of the video & audio. Hence, you can expect an HDMI cable to deliver the finest resolution among all other consumer interfaces.
However, HDMI cables have no role in the signal or data compression by broadcasters and streaming services. HDMI can only minimize or even prevent any signal loss in transit from its source to the output device.
Also read: HDMI vs. Optical Audio Cables (Sound Qualities Compared)
What Are the Types of HDMI Cable?
The main types of HDMI cables are Standard, High-Speed, Premium, and Ultra. Each type has more than one HDMI version or generation. Also, the Standard and High-Speed HDMI cables have Ethernet variants, whereas Premium and Ultra don’t have regular versions.
Here are the types of HDMI cables per the main classifications:
- Standard: 1.0, 1.1, and 1.2
- High-Speed: 1.3, 1.3a, 1.4, and 1.4a
- Premium: 2.0, 2.0a, and 2.0b
- Ultra: 2.1 and 2.1a
HDMI Cable Bandwidth
All HDMI cables have a bandwidth that determines the transmission rate. Here are the currently available bandwidths for the different generations or types of HDMI cables.
- 4.95 Gb/s: HDMI 1.0, HDMI 1.1, and HDMI 1.2
- 10.2 Gb/s: HDMI 1.3 and HDMI 1.4
- 18 Gb/s: HDMI 2.0
- 48 Gb/s: HDMI 2.1
These bandwidths are the higher limits for each HDMI cable. So, the transmission rates for the actual data transfer are unlikely to be the maximum available bandwidth. Besides, HDMI cables allocate some bandwidth to sustain the connections with the devices.
HDMI Cable Video Resolution
All HDMI cables released to date can be classified into the following video resolution categories:
- 1080p: HDMI 1.0
- 1440p: HDMI 1.1 and HDMI 1.2
- 4K: HDMI 1.3 and HDMI 1.4
- 5K: HDMI 2.0
- 8K: HDMI 2.1
HDMI cables 1.3 and 1.4 have identical bandwidths or transmission rates and video resolutions. Also, you will notice in the following section that they don’t have any difference in regards to the compatible audio support standards.
However, HDMI 1.4 was a quantum leap from the 1.3 type that changed the way we use these cables. I discuss this paradigm shift in the special features section.
HDMI Cable Audio Support
The first HDMI cable (1.0) had 8 channels for audio support. HDMI 1.1 and HDMI 1.2 supported One-Bit and DVD audio standards.
HDMI 1.3 and HDMI 1.4 upped the game with support for DTS-HD Master and Dolby TrueHD audio formats. HDMI 2.0 expanded the audio support channels to 32.
The latest HDMI 2.1 has an enhanced 1536 kHz sample frequency in addition to all the other preexisting audio support features.
HDMI Cable Special Features
HDMI cables are a technological marvel. Not only did HDMI combine digital video and audio transfer into a single cable, but the technology also created the foundation that has now led to the rollout of more than 2 dozen features. In other words, HDMI is not just a cable. Here’s why:
Consider the first HDMI cable. HDMI 1.0 supported sRGB and YCbCr. The audio support was limited to 24-bit and 192 kHz through an 8-channel LPCM. But even HDMI 1.0 supported the full resolution of HD DVD and Blu-Ray. Also, it introduced the Consumer Electronics Control (CEC).
Remember the 7 more wires apart from the 12 used for data transfer, clock signals, and shields. One of these wires is dedicated to the Consumer Electronics Control. This HDMI-CEC feature is often branded by a few companies, such as Simplink (LG) and Anynet+ (Samsung).
HDMI 1.1 and 1.2
While HDMI 1.0 transformed the world of audiovisual entertainment and gaming, the next two editions weren’t pioneering per se. HDMI 1.1 added only one extra feature, support for DVD audio. HDMI 1.2 added another feature, support for Super Audio CD.
HDMI 1.3 added several useful features, like Deep Color. The most important of these features was the support for Dolby TrueHD and DTS-HD Master Audio. However, HDMI 1.4 stole 1.3’s thunder as it changed the fundamentals of connecting compatible audio-video devices.
HDMI 1.4 introduced 3D support and 4K compatibility at 30 frames per second. However, the showstoppers for HDMI cable 1.4 were the Audio Return Channel (ARC) and Ethernet. The first HDMI cable that could route sound from a TV to a soundbar was the 1.4 edition.
HDMI 1.4, with its Audio Return Channel feature, eliminated the need for other wires to connect a TV or display with a speaker or audio output device. Additionally, the ARC feature enables you to enjoy the original audio without any loss of signal or quality.
Suppose the original audio of something you want to watch is surround sound. The HDMI 1.4 cable and subsequent generations will deliver the surround sound to your audio device without any compression and significant signal loss. So, the quality of the output is the best you can get.
HDMI 2.0 marked the beginning of the 4K era for cable interfaces.
While HDMI 1.4 supports 4K, the lower frame rate is unimpressive. An HDMI cable 2.0 can support 4K resolution at up to 60 frames per second. Also, HDMI 2.0 introduced native audio support for HE-AAC and DRA with 32 channels.
Furthermore, HDMI 2.0 cables support 2 video and 4 audio streams. Plus, the version supports a 21:9 aspect ratio. However, these features may not be relevant for everyone. The paradigm shift with HDMI 2.0, apart from 4K support, is probably the HDR feature (High Dynamic Range).
HDMI 2.1 is the singularly greatest leap since the release of 1.4.
An HDMI 2.1 cable has an enormous bandwidth of 48 Gb/s and supports video resolutions of 8K. This generation of HDMI cables has all the other preexisting features, including HDR, and the subsequent editions are likely to increase the fps support for up to 10K resolution.
Also, HDMI 2.1 has eARC (Enhanced Audio Return Channel). This feature rests on the massive bandwidth. The first HDMI cables supported uncompressed and compressed audio. But a 48 Gb/s bandwidth has more than sufficient transmission rate for absolutely uncompressed sound.
Also read: How Many HDMI Cables do you Need?
What Types of Connections Do HDMI Cables Use?
HDMI cables use 5 types of connections: A (standard), B (dual-link), C (mini), D (micro), and E (industrial, automotive, etc.). People typically use the standard type A HDMI cable. However, most cameras and smartphones need type C and D HDMI cables, respectively.
Thus, a majority of users have only types A, C, and D. Type B or dual-link HDMI cable is not really available, but the E connection is used in specific installations when the other sizes won’t work. So, let me put the spotlight on standard, mini, and micro HDMI cables.
Here are the dimensions of the popular HDMI cable connections:
- Type A (Standard): 13.9 mm by 4.45 mm (0.55 inches by 0.17 inches)
- Type C (Mini): 10.42 mm by 2.42 mm (0.41 inches by 0.09 inches)
- Type D (Micro): 6.4 mm by 2.8 mm (0.25 inches by 0.11 inches)
Despite the differences in dimensions, these HDMI cable connectors have 19 pins. Also, every HDMI cable in these three sizes has the same features that it is supposed to have based on its generation or version.
Thus, an HDMI cable version 1.4 has the same bandwidth, resolution, and other features for connectors A, C, and D. However, the pins don’t have the same alignment or function in the standard, mini, and micro types of connectors.
So, the Consumer Electronics Control (CEC) pin connecting a standard HDMI cable 2.0 to your HDTV may not be the same one in a mini or micro variant of the same generation that you hook to a camera or smartphone. Such alignment variations don’t affect the users, though.
What can affect you is the connecting mechanism and device compatibility. Standard, mini, and micro HDMI cables don’t have a locking system for you to secure them to compatible ports.
The 19-pin male connection requires a female receptacle on both input and output devices, and you slide the HDMI cable into both ports using the accurate orientation like you use a USB. However, you may want an HDMI cable that connects more securely, similar to the VGA or DVI screws.
Technically, you don’t need a fastening mechanism to secure an HDMI cable in any receptacles. Still, there are HDMI cables with gripping or locking features. You can also shop for right-angled HDMI cables or panel-mounted connectors.
Another connection issue you may encounter is the compatibility of a port. Choosing the right size or type of connector isn’t sufficient. You need to have the right type of HDMI cable and the size you need for compatible input and output receptacles.
Consider the following instances:
- HDMI: You need two compatible ports for the type, size, or connector of the cable.
- HDMI ARC: You need one ARC (Audio Return Channel) port on the device that will route the sound through an HDMI cable with this feature.
- HDMI eARC: You need the HDTV or source device to have an HDMI eARC receptacle to be compatible with such cables, regardless of the size or connector type.
HDMI 1.0, 1.1, 1.2, and 1.3 are passe. HDMI 1.4 is still around. However, current choices are really between HDMI 2.0 and 2.1, including their variants. The types aside, the size or connector is simply about the compatible ports, irrespective of locking mechanisms.
The first HDMI cable was primarily a single interface for uncompressed and high-resolution video and audio. Now, HDMI cables deliver 4K and are 8K-ready with Ethernet, eARC, HDR, and several valuable features. Only time can reveal how HDMI cables will evolve hereafter.
Jason is a home theater expert with over 10 years of experience in setting up home cinema rooms and systems. What started out as a hobby soon transformed him into an authority in the audio-visual field. He is passionate about providing readers with accurate and up-to-date information on the latest audiovisual technologies and their applications for home theaters. Read more about Jason.