HDMI Technology Includes:
HDMI - the basics HDMI versions HDMI connectors Pinout / pin connections HDMI cables USB C to HDMI HDMI & DVI HDMI switch, splitter & matrix - the differences HDMI extenders HDMI repeaters Essential HDMI products
There are five types of HDMI connector. Although the main type seen on televisions and other domestic AV equipment is the most widely used, and probably the most robust, other types exist for other applications as well.
The most common HDMI connector is the type A connector and along with the Type B, these were launched with the initial standard. Other types have been introduced since then to meet specific needs.
The HDMI system and the accompanying connectors and leads are able to enable the high speed transfer of high quality and bandwidth AV signals along with providing for other associated capabilities. The connectors are manageable whilst remaining robust and reliable.
In many respects some HDMI connectors look quite similar to USB connectors. However there are differences in size and particularly the number of wires in the cable and connector. HDMI connectors & cables have 19 wires / connections and this is significantly more than the USB connector.
HDMI connector types
The different HDMI connector types have remained unchanged after their introduction. This has enabled backwards compatibility to be maintained over the life of the standard.
With the exception of the dual link Type B connector, they all have 19 pins enabling the standard to remain the same across all connector types.
In view of the different sizes, the different HDMI connectors tend to be used on different types of equipment.
Summaries of the different HDMI connector types are given below:
- HDMI Type A connector: This connector was launched with the original standard and has been the mainstay of the HDMI standard since then. The Type A connector is the one that is the most familiar to users of AV equipment and it is found on a huge number of items from televisions, DVD players, satellite boxes, recorders, games consoles and many more items. Where space is not an issue, the Type A HDMI connector is ideal as it is the most robust.
The plug or male connector has outside dimensions of 13.9 mm × 4.45 mm, and the receptacle or female connector has inside dimensions of 14 mm × 4.55 mm.
There are 19 pins and the bandwidth is able to carry all SDTV, EDTV, HDTV, UHD, and 4K modes. This connector type is electrically compatible with single-link DVI-D.
The male version of the HDMI Type A connector is widely available on ready made leads as well as connectors for self assembly. Many of the female versions are also available for incorporation into AV equipment. There is a good selection, so the one with the required dimensions, format and specification can be chosen.
- HDMI Type B connector: This type of HDMI connector was also launched with the original standard in 2002 and it is aimed at carrying dual link DVD-I video. The connector has never been used in products because with the introduction of HDMI 1.3, the speed of a single link exceeded that of the old dual link. As the connector is larger than the single link standard style, there has been no reason for its use. However it is still retained within the specifications.
This type of HDMI connector measures 21.2 mm × 4.45 mm and has 29 pins, carrying six differential pairs instead of three.
- HDMI Type C connector - Mini-HDMI connector: This is the mini-HDMI connector and is smaller than the Type A connector, measuring 10.42 mm × 2.42 mm but still retaining the 19-pin configuration. The mini-HDMI retains all the functionality of the larger HDMI Type A, but the connector is much smaller.
The HDMI mini connector was introduced in HDMI Version 1.3 as the HDMI standard became more widely accepted and the need for a smaller connector was recognised.
There are differences in the mini-HDMI connector connection configuration: all positive signals of the differential pairs are swapped with their corresponding shield, the DDC/CEC Ground is assigned to pin 13 instead of pin 17, the CEC is assigned to pin 14 instead of pin 13, and the reserved pin is 17 instead of pin 14.
The HDMI Type C connector can be connected to a type A connector but it requires the use of a type A-to-type C cable or an adapter.
The mini-HDMI connectors are very common on many pieces of portable equipment. Some examples include: DSLR cameras, camcorders, larger tablets, sat nav systems and the like.
- HDMI Type D connector - micro-HDMI connector: The size of the HDMI Type D connector is very similar to the micro-USB connector and as a result the Type D is often known as a micro-HDMI connector.
The measurements are just 6.4 mm × 2.8 mm and within this outline the micro-HDMI retains the 19 pins of the other connectors, although the pin assignments are different. The micro-HDMI connector was introduced with HDMI Version 1.4. It was developed specifically for audio-video connectivity in small and portable devices like mobile phones.
- HDMI Type E connector: The Type E HDMI connector is aimed at automotive applications. This connector was introduced with HDMI Version 1.4.
In order to prevent it vibrating loose it incorporates a locking tab and also a shell to help prevent dirt and moisture from entering. Additionally a relay connector is available for connecting standard consumer cables to the automotive ones and enabling an interface to consumer AV items which is happening increasingly.
Female and male HDMI connectors
There is a convention for connectors that the source of power, data, audio etc has a female connector and the item taking the power, audio, etc is male. The reason for this is that the female connector pins, by the very nature of a female connector are protected and cannot suffer a short circuit by the accidental shorting by an external metallic object.
However many modern connectors also have male areas that are protected and there is less chance of short circuits.
Accordingly female HDMI connectors are usually built into both the static devices at either end of the connection, e.g. a TV or display, and a computer , DVD, etc. In other words female HDMI connectors are present on the signal source device and the receiving device. Male HDMI connectors are then attached to both ends of the connecting cables.
Part of the reason for this is that many of the communications occur in both directions and therefore, even though one may be a signal source as such, the receiving device still sends signals and other data out. As a result is is sensible to adopt the strategy that the devices have female connectors and the cables have male HDMI connectors.
Normally the female HDMI connectors are recessed into the body of the various devices but even so they tend to be damaged more easily as a result of the strain sometimes applied accidentally if the cables are pulled in the wrong direction, etc. As a result, the female HDMI connectors tend to be sold more frequently as replacement connectors!
Even if male connectors on a cable are damaged on the shorter commercially made HDMI cables, the difficulty of replacing them and the cost of the connector compared to a new HDMI cable means that a new HDMI cable is bought rather than trying to attempt a repair.
Straight & right angled HDMI connectors
The most obvious format for a connector is to have one that, when plugged in to the receptacle, the cable from the free connector extends outwards from the connection. This is suitable for most applications, but it can require some space for the cable to bend to the direction in which it needs to be routed.
There are some instances where a very sharp bend might be needed. This bend might need to be too sharp to be accommodated by the HDMI cable. This could put too much strain on the HDMI connector and cable.
Right angles HDMI connectors are very useful where equipment may be close to a wall or panel within a cabinet, etc. The cable coming out of the connector will travel alongside the equipment and not require a very sharp bend to enable it to fit within the space available.
If an HDMI cable with a right angled connector is not available, then right angled adaptors are available. These should generally not be used unless necessary as they add a further connection into the cabling, and will not be as firm as a single HDMI connector, but they nevertheless resolve an issue and can be used for the short term.
HDMI connector adapters
There are many cables that enable HDMI Type A connections to interface with mini-HDMI or microHDMI. These cables are widely available and will be able to provide the full HDMI capability, consistent with the capability of both ends of the link.
These cables are very useful because they do not require the use of an HDMI connector adapter, and a cable is required anyway to link the two items together.
There are some instances where a connector adapter may be needed. It can be particularly useful to have a set of HDMI adaptors to link Type A to mini-HDMI or micro-HDMI connectors when setting up systems when the correct cables may not be available.
Check out the Electronics Notes: Essential HDMI Items List.
The variety of HDMI connectors ensures that the HDMI standard can be successfully used in many different areas and they can accommodate the requirements of users of the many different applications for which HDMI is used.