VGA (D-Sub) - what kind of interface it is, types, features, pros and cons of the connector. Monitor Interfaces - Connector Types Ideal Connector Design

It is designed for connecting a PC or laptop to monitors, TVs, etc. The D-SUB connector (second name is VGA) was present on all computer video cards, but in Lately he was forced out new standard- DVI interface. Nevertheless, this type is still common in the filling of “old iron”.

Interface description

The D-SUB connector contains a block with pin contacts arranged in two, three or four rows. The number of pins in the first row is one more than in the second. The contacts are protected by a special metal casing, the profile of which resembles the shape of the letter D. This eliminates the possibility of incorrect connection of the connector.

Connectors of this series (both socket and plug) can have a different number of contacts:

As a rule, D-SUB connectors (to ensure a reliable connection) undergo additional processing. Thus, the contacts of this device can be coated with gold or tin (tinning). This interface is installed on a block, board or cable. In the latter case, use different types buildings. Such connectors are widely used for data transmission in many interfaces, as well as for supplying power to various different devices.

D-SUB connector: classification


  • DRB - horizontal (right angle). There are three modifications: A = 7.2 mm, B = 9.4 mm, C = 13.8 mm. These values ​​correspond to the distance from the edge of the connector to the first row of contacts.
  • DBB - vertical. On the inside of the connector there are cylindrical leads that are soldered into the board.
  • DRN - paired (combined). They are a single block that consists of 2 or 3 D-SUB connectors with different numbers of pins. The compact size of the connector saves space on printed circuit boards.

D-SUB MIL-C connectors

This type of connector is intended for use in military equipment. Such connectors are considered power connectors and can be mounted on cables of various sizes. There are modifications with replaceable crimp terminals. Connectors in this series have more stringent requirements for technical specifications. They have very robust housing, resistant to environmental influences. These devices respond high requirements reliability, but their use is very limited due to their high cost.

D-sub(D-subminiature) - popular in computer technology line of electrical connectors. When it appeared on the market, the “subminiature” connector fully justified its name. However, today, it can hardly be called such; rather, on the contrary, it is one of the most massive computer signal connectors.

Description

The D-sub interface includes two (or more) parallel rows of pins and sockets. As a rule, they are surrounded by a metal shield shaped like the Latin letter D. It mechanically connects the connector to the plug and also shields the interface from electromagnetic interference. A connector with this unique shape is very convenient because it eliminates incorrect connection. The side of the connector that contains the contacts is called male connector ("dad"), another containing nests - female connector ("Mother"). The socket shield fits inside the plug shield. If shielded cables are used, the connector shields are connected to the cable shields. This ensures continuous shielding of the entire connection.

D-sub connectors were created by ITT Cannon, a division of ITT Corporation. The date of creation of the connector is distant 1952. The designation system adopted within the company indicates that the symbol “D” designates the entire series of D-sub connectors; the second letter is used to indicate the size of the connector, which depends on the number of standard pins located inside the D-shaped shield (A = 15, B = 25, C = 37, D = 50, E = 9); then the number of actually used contacts is located, and with it the letter that characterizes the “gender” of the connector: M - “male”, F - “female”, P - plug/male, S - socket/female. For example, DB25M needs to be decrypted in the following way: D-sub connector with shield, and the actual number of contacts is 25. The contacts in the connector are spaced at a distance of 2.77 mm, the rows are spaced at a distance of 2.84 mm.

Cannon also produces D-sub connectors with connections that have larger connectors than conventional pins. These connectors can be used for both high voltage and coaxial connections. They take the place of several standard contacts at once.

Name confusion

Due to the widespread use of DB-25 connectors for parallel and serial ports, most users, not realizing that “B” denotes screen size, began to call the D-sub connector itself differently: DB. Although, according to the rules, designations like “DA”, “DC”, or “DE” should have been used. The same applies to the DB9 connector, which they started calling ordinary 9-pin connectors, although they should have called them DE9. This has led to the fact that DE9 connectors are now often sold on the market as DB9. By DB9 they often mean a 9-pin connector with screen size E.

Currently, there are special D-sub connectors that have a standard screen size, but at the same time have a larger number of pins, and the names use the same nomenclature.

There are connectors with even higher pin densities, called “double density”: DE19, DA31, DB52, DC79 and DD100. All connectors have four rows of contacts.

In addition, there is another family of connectors that are often confused with D-sub, although this family is not included in this standard. These connectors are called, for example, HD50 and HD68. They also have a D-shaped connector, but this connector is almost twice as thin as the DB25. Such connectors are usually used in SCSI connections.

D-sub connectors are described in DIN 41652.

Application

D-sub connectors are very popular in the field of data transmission via the RS-232 serial interface, despite the fact that the standard does not require its use for these purposes. Initially, RS-232 used DB25, but due to the fact that many applications used only part of the pins, it became possible to implement 9-pin DE9 connectors for these purposes.

In PCs, 9- and 25-pin connectors are used for:

  • serial port (RS-232);
  • parallel (IEEE 1284) printer port.

The IEEE 1284 standard uses a DB-25 connector on the PC side, called "IEEE 1284-A", and on the printer side, it uses an "IEEE 1284-B" connector (borrowed from Centronics).

The DE9 plug on the back of an IBM PC typically has an RS-232 connector. It was first used in PCs in 1984. There was also usually a 9-socket socket, which served as a video card output to a monochrome, CGA, or EGA monitor. Despite the fact that all interfaces used a single connector, only a certain type of monitor was used with the video card, since connecting a monitor of a different type could result in the monitor burning out.

More modern video cards, standard VGA, used the DE15 connector, it had 15 contacts arranged in 3 rows. This connector is also known as HD15, where HD = High Density.

Today, the D-sub designation in video card descriptions is used only for DE15 connectors.

By the late '70s and throughout the '80s, non-screw-type DE9 connectors were everywhere used for connecting control devices. The connector became a de facto standard after it began to be used in game console Atari 2600, as well as in the Atari line of 8-bit computers. In addition, these computer connectors are used by the following systems: Atari, Commodore, Amstrad, SEGA.

Many sources uninterruptible power supply is equipped with a DE9F connector, which performs the functions of exchanging signals with a computer - in order, for example, to report the battery charge level. Most of these devices are not used standard interface serial port, but its own wiring, which different manufacturers varies. Some companies deliberately use non-standard wiring to compete: to force the user to use their proprietary cable.

In addition, the following connectors are also used in D-sub technology:

  • 15-pin DA15 (two rows: 7 and 8 pins) - used to connect a color monitor in early Mac computers, as well as for connecting to network cards;
  • 37-pin DC37 (two rows: 18 and 19 pins);
  • 50-pin DD50 (two rows of 17 and one row of 16 pins).

The standard provides simultaneous transmission of visual and audio information per cable, it is designed for television and cinema, but PC users can also use it to output video data using the HDMI connector.


HDMI is another attempt at standardization universal connection for digital audio and video applications. It immediately received strong support from the giants of the electronics industry (the group of companies developing the standard includes companies such as Sony, Toshiba, Hitachi, Panasonic, Thomson, Philips and Silicon Image), and most modern output devices high resolution has at least one such connector. HDMI allows you to transmit copy-protected audio and video in digital format over a single cable; the first version of the standard was based on a bandwidth of 5 Gb/s, and HDMI 1.3 expanded this limit to 10.2 Gb/s.

HDMI 1.3 is the latest standard specification with increased interface bandwidth, increased clock frequency up to 340 MHz, which allows you to connect high-resolution displays that support more colors (formats with color depths up to 48-bit). New version specifications defined and support for new Dolby transmission standards compressed audio without loss in quality. In addition, other innovations appeared; specification 1.3 described a new connector, smaller in size compared to the original.

In principle, the presence of an HDMI connector on a video card is completely optional; it can be successfully replaced by an adapter from DVI to HDMI. It is simple and therefore included with most modern video cards. Moreover, on video cards of the HDMI series the connector is in demand primarily on mid-range and lower levels, which are installed in small and quiet barebones used as media centers. Because of the built-in audio, the Radeon HD 2400 and HD 2600 graphics cards have a definite advantage for builders of such multimedia centers.

Based on materials from the company's website iXBT.com

#VGA #DVI-D #DVI-I #HDMI #DisplayPort

Interfaces currently in widespread use:

VGA

(D-Sub)- the only analog interface for connecting monitors still in use today. It is morally obsolete, but will be actively used for a long time. Main disadvantage is associated with the need to use double conversion of the signal to analog format and vice versa, which leads to a loss of quality when connecting digital display devices (LCD monitors, plasma panels, projectors). Compatible with video cards with DVI-I and similar connectors.

DVI-D

- basic type of DVI interface. Implies only digital connection, therefore cannot be used with video cards that only have an analog output. Very widespread.

DVI-I

- an extended version of the DVI-D interface, the most commonly used nowadays. Contains 2 types of signals - digital and analog. Video cards can be connected via both digital and analog connections; a video card with a VGA (D-Sub) output can be connected to it via a simple passive adapter or a special cable.
If the documentation for the monitor indicates that this modification uses the DVI Dual-Link option, then in order to fully support the maximum monitor resolutions (usually 1920*1200 and higher), the video card and the DVI cable used must also support Dual-Link as a full interface option DVD-D. If you use the cable included with the monitor and a relatively modern (at the time of writing the FAQ) video card, then no additional purchases are required.

HDMI

- adaptation of DVI-D for household equipment, supplemented by a digital interface for multi-channel audio transmission. Present in virtually all modern LCD TVs, plasma panels and projectors. To connect a video card with a DVI-D or DVI-I interface to the HDMI connector, a simple passive adapter or cable with appropriate connectors is sufficient. It is impossible to connect a video card with only a VGA (D-Sub) connector to HDMI!

Legacy and exotic interfaces:

31. 01.2019

Blog of Dmitry Vassiyarov.

D-sub connector and what can be connected to it

I am glad to welcome you, my friends.

I decided to expand the collection of my articles concerning contact interfaces used in computers and other equipment. Those interested in this topic always ask the question: D-sub connector, what is it? It is truly worthy of your attention because for a long time was the most common, and is still successfully used in some devices.

The history of the name of this connector is very original. If the designations we are familiar with, USB, HDMI, are an abbreviation of the English definition, then in the case of D-sub everything is different.

Its full name is “D-subminiature”, where D is a simplified designation of the shape of the connector itself, which from a geometric point of view is a trapezoid with rounded corners and, naturally, resembles this letter. “Subminiature” – “very miniature”. At one time, without false modesty, this was the most accurate description of the dimensions of the innovative connector.

For the first time, experts saw the Di-Sub pin connector in 1952 in the products of the American company ITT Cannon, part of the international corporation ITT. ITT Corporation worked closely with the US Defense Department. And its development was created with the prospect of use in military equipment.

Ideal connector design

The ITT Cannon specialists coped brilliantly with the task of reducing the number of wires and connections, as well as minimizing the area occupied by connectors, because their universal brainchild, the D-sub connector in different options execution has existed for more than half a century and is still in demand in some devices. Let's take a look at it:

  • The base of the connector is an insulating plate made of plastic (polystyrene, sometimes reinforced with fiberglass). It serves as a mount and separator for contacts.
  • Along its perimeter there is the same galvanized (or tinned) steel plate, reminiscent of the letter D. This is an important structural element that performs three functions at once:
  • It is the basis for reliable fastening of the plug in the socket;
  • Protects (screens) transmitted signals from possible electromagnetic interference;
  • Its shape determines the mutual orientation of the corresponding contacts and makes incorrect connection impossible;
  • In the classic version, the contacts are thin pins (and, accordingly, tubes in the socket) made of nickel-plated bronze. The most critical connectors use gold plating. The contacts are arranged in two or three rows at an equal distance from each other with normal or increased density. The number of contacts is strictly fixed and determined by the data transfer protocol and the power system. There are D-sub with 9, 15, 25, 37, 50 and more contacts.

  • In some connector modifications, thin pins can be supplemented with reinforced contacts to transmit a coaxial signal or powerful power supply. They are used, for example, to transmit high-quality images with RGB division of the analog signal.

The housing is an equally important part of this connector.

  • As such, it is present only on the fork and can be solid or dismountable (with screws or latches for quick assembly). Made from durable plastic or metal (steel, aluminum). A special feature of the D-sub plug housing is the presence of two mounting screws that attract it to the socket and prevent accidental disconnection of the contacts. Their tightening from the fork side can be done with a special tool or manually, due to the grooved notches on the head of the screws.

This connector, like any other, is divided into two parts. The plug (plug) contains pin contacts and an outer (encompassing) shield.

This part connected to the external cable is also called “plug”, “male” or “male connector”.

The socket has an internal screen and contacts made in the form of tube sockets. This item also called “mother”, “socket” or “female connector”. English versions of designating wording are used in labeling.

Attaching the cable to the contacts

One of design features The D-sub connector has a variety of ways to connect to the cable:

  • Soldering, according to experienced specialists, is, although labor-intensive, but also the most reliable installation method. To facilitate this procedure, the back side of the contacts is made in the form of a semi-cylindrical or flat surface;

  • Removable crimp contacts allow you to speed up the connection process. After this operation is completed, they are placed back into their slots on the insulator;
  • In the case of using a cable cable, you should give preference to connectors with a device for pinning contact surfaces;

  • The fastest to install is D-sub with a self-clamping device. You will need to arrange the wires into contact cells and secure them with a special insert.

The fastening structures provide cable outlets in different directions (straight or at an angle).

Learning to unravel unusual markings

Now that we have learned about the variety of D-sub connectors, I propose to talk about their markings. And here we are faced with confusion. The fact is that ITT Cannon proposed letter designations for different sizes corresponding to a certain number of contacts.

But their number is already indicated in the designation. Writing extra letters is not entirely reasonable. Although many, out of habit, often indicate “B” (corresponding to 25 contacts). So you may well encounter a DB9S or DB50M. Don’t pay attention to “B”, but take a closer look at the last letter. Remember the previous conversation about plugs and sockets. So in this case, these are “socket” and “male connector”, respectively.

The marking also contains the letter “W” with a number indicating the presence of additional reinforced contacts, and the combination “HD” indicates a high density of plugs and sockets.

Continuing the conversation about D-sub designations, it is worth noting that the companies involved in their production offer their own options for marking the method of fastening the wires and the location of the cable. And yet, if you find “MIL” in the name of the connector, this will indicate its high quality and reliability meeting US Department of Defense standards.

What is D-sub for?

Parameters for using Di-Sub connectors are cable lines with a current of up to 5 amperes, with an insulation resistance of 1000 MΩ and contact resistance of 30 MΩ. This is information for specialists, but we are interested in what D-sub is used for.

This connector was created based on telecommunications needs, and implied the use of the RS-232 protocol to connect the modem to a computer. This interface provided high reliability for serial signal transmission. This is why the PC serial port got its name. Although he had a short throughput, but was unpretentious in operation and was simply programmed for different purposes.

Thanks to this, almost all devices connected to computing and network devices(before the USB era) used a D-sub connector.

Their list is quite large, but here are just some well-known examples:

  • game consoles and joysticks;
  • network adapters and modems;
  • printers;
  • uninterruptible power supplies;
  • mice.

Do you need examples? The older generation probably remembers a computer like the ZX Spectrum? So it had an expansion port into which you could plug in all sorts of cool things, like a printer or a joystick.

But of course, the most common use of this connector to this day is the transmission of video signals to TVs, projectors and monitors. It is of course being replaced by digital. But where there is only a DB15HD socket, you can still get a picture with HD resolution.

Having touched on the topic of connecting to different devices, it should be said that in some cases it is necessary to use adapters between D-sub with a different number of contacts. There are also adapter options between DVI and VGA version of “Di-Sub”.

This, friends, is the legendary D-sub connector. Now you have learned a lot about him and have probably gained respect for this fighting “old man”. And I finish my story and wish everyone the best. See you again on my blog.