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Insight - How VGA Connector Works

Written By: 

Abhimanyu Mathur

 

VGA connectors are sub miniature D type graphic connectors which are primarily used for connecting CPUs to monitors. The shape of the metal shield of these connectors resembles a “D”, hence the name “D” type connectors.

Since their invention in the year 1987, these graphic connectors have come a long way. From interfacing desktop computers to light weight tablet computers, VGA connectors serve as one of the most inexpensive video interfaces for smart computing devices. It is quite interesting to note that even though these connectors were developed by IBM PC, it was their counter rivals Apple Inc. who preferred these connectors for iPad. An interesting history with a mass applicative scenario, VGA connectors get demystified in this Insight. 

Image of 15-pin VGA Connector

Fig. 1: Image of 15-pin VGA Connector

Pin Outs: A 15 pin VGA connector is seen in Image 01 above. The pins, in three rows of five as shown in the image, are placed in a plastic molding which is surrounded by a metal casing.

The pin-outs are:

Pin

Name

Type

Description

1

RED

Output

Red Video (75 ohm, 0.7 V p-p)

2

GREEN

Output

Green Video (75 ohm, 0.7 V p-p)

3

BLUE

Output

Blue Video (75 ohm, 0.7 V p-p)

4

ID2

Input

Monitor ID Bit 2

5

GND

-

Ground

6

RGND

-

Red Ground

7

GGND

-

Green Ground

8

BGND

-

Blue Ground

9

KEY

-

Key (No pin)

10

SGND

-

Sync Ground

11

ID0

Input

Monitor ID Bit 0
GND=Color; NC=Mono

12

ID1 or SDA

Input

Monitor ID Bit 1
NC=Color; GND=Mono
Some systems only uses ID0 for monitor ID

13

HSYNC or CSYNC

Output

Horizontal Sync (or Composite Sync)

14

VSYNC

Output

Vertical Sync

15

ID3 or SCL

Input

Monitor ID Bit 3

Table 1: Showing pins, their Types, and Respective Description

Output Pins & Moldings

Output Pins at Reverse End of Connector

Fig. 2: Output Pins at Reverse End of Connector

Output Pins: Corresponding to the 15 pins that interface with the device are the pins on the opposite side that are soldered to wire.

VGA Connector Pins Embedded in Plastic Molding

Fig. 3: VGA Connector Pins Embedded in Plastic Molding

Plastic MoIdings: In Image 03, the metal casing is opened to show the placement of pins in the plastic molding.

Connector Pins & their Structure

VGA Connector Pins and Structure

Fig. 4: VGA Connector Pins and Structure

VGA Connector Pins: Pins of the connector are not sturdy enough and get bent on application of slightest force. This is why they are sheathed by a protective metal casing. Once the casing is removed, the pins are plucked out from the plastic moldings.

Image of a Single Pin Indicating its Structure

Fig. 5: Image of a Single Pin Indicating its Structure

Pin Structure: Image 05 provides a clear picture of the structure of the pin. The end that gets soldered to the wiring is flattened. Proceeding towards the end where male and female connector interface, the pin attains a cylindrical shape.